test: replace busted with local harness

Replace the busted-based Lua test runner with a repo-local harness.

The new harness runs spec files directly under `nvim -ll`, ships its own
reporter and lightweight `luassert` shim, and keeps the helper/preload
flow used by the functional and unit test suites.

Keep the file boundary model shallow and busted-like by restoring `_G`,
`package.loaded`, `package.preload`, `arg`, and the process environment
between files, without carrying extra reset APIs or custom assertion
machinery.

Update the build and test entrypoints to use the new runner, add
black-box coverage for the harness itself, and drop the bundled
busted/luacheck dependency path.

AI-assisted: Codex

.github/workflows/test.yml

@@ -74,10 +74,6 @@ jobs:
         name: luals
         run: cmake --build build --target luals
 
-      - if: success() || failure() && steps.abort_job.outputs.status == 'success'
-        name: luacheck
-        run: cmake --build build --target lintlua-luacheck
-
       - if: success() || failure() && steps.abort_job.outputs.status == 'success'
         name: lintsh
         run: cmake --build build --target lintsh

.luarc.json

@@ -4,9 +4,6 @@
     "version": "LuaJIT"
   },
   "workspace": {
-    "library": [
-      "${3rd}/busted/library"
-    ],
     "ignoreDir": [
       ".deps",
       "build",

BUILD.md

@@ -569,7 +569,7 @@ Note that the C++ compiler is explicitly set so that it can be found when the de
 
 See "Available System Integrations" in `zig build -h` to see available system integrations. Enabling an integration, e.g. `zig build -fsys=utf8proc` will use the system's installation of utf8proc.
 
-`zig build --system deps_dir` will enable all integrations and turn off dependency fetching. This requires you to pre-download the dependencies which don't have a system integration into `deps_dir` (at the time of writing these are ziglua, [`lua_dev_deps`](https://github.com/neovim/deps/blob/master/opt/lua-dev-deps.tar.gz), and the built-in tree-sitter parsers). You have to create subdirectories whose names are the respective package's hash under `deps_dir` and unpack the dependencies inside that directory - ziglua should go under `deps_dir/zlua-0.1.0-hGRpC1dCBQDf-IqqUifYvyr8B9-4FlYXqY8cl7HIetrC` and so on. Hashes should be taken from `build.zig.zon`.
+`zig build --system deps_dir` will enable all integrations and turn off dependency fetching. This requires you to pre-download the dependencies which don't have a system integration into `deps_dir` (at the time of writing these are ziglua and the built-in tree-sitter parsers). You have to create subdirectories whose names are the respective package's hash under `deps_dir` and unpack the dependencies inside that directory - ziglua should go under `deps_dir/zlua-0.1.0-hGRpC1dCBQDf-IqqUifYvyr8B9-4FlYXqY8cl7HIetrC` and so on. Hashes should be taken from `build.zig.zon`.
 
 See the `prepare` function of [this `PKGBUILD`](https://git.sr.ht/~chinmay/nvim_build/tree/26364a4cf9b4819f52a3e785fa5a43285fb9cea2/item/PKGBUILD#L90) for an example.
 

CMakeLists.txt

@@ -243,15 +243,6 @@ mark_as_advanced(TS_QUERY_LS_PRG)
 
 set(STYLUA_DIRS runtime scripts src test contrib)
 
-add_glob_target(
-  TARGET lintlua-luacheck
-  COMMAND $<TARGET_FILE:nvim_bin>
-  FLAGS -ll ${PROJECT_SOURCE_DIR}/test/lua_runner.lua ${CMAKE_BINARY_DIR}/usr/share/lua/5.1 luacheck -q
-  GLOB_DIRS runtime scripts src test
-  GLOB_PAT *.lua
-  TOUCH_STRATEGY PER_DIR)
-add_dependencies(lintlua-luacheck lua_dev_deps)
-
 add_glob_target(
   TARGET lintlua-stylua
   COMMAND ${STYLUA_PRG}
@@ -271,7 +262,7 @@ add_custom_target(lintlua-stylua2
 add_dependencies(lintlua-stylua lintlua-stylua2)
 
 add_custom_target(lintlua)
-add_dependencies(lintlua lintlua-luacheck lintlua-stylua)
+add_dependencies(lintlua lintlua-stylua)
 
 add_glob_target(
   TARGET lintsh
@@ -355,21 +346,6 @@ ExternalProject_Add(uncrustify
   EXCLUDE_FROM_ALL TRUE
   ${EXTERNALPROJECT_OPTIONS})
 
-option(USE_BUNDLED_BUSTED "Use bundled busted" ON)
-if(USE_BUNDLED_BUSTED)
-  get_externalproject_options(lua_dev_deps ${DEPS_IGNORE_SHA})
-  ExternalProject_Add(lua_dev_deps
-    DOWNLOAD_DIR ${DEPS_DOWNLOAD_DIR}/lua_dev_deps
-    SOURCE_DIR ${DEPS_SHARE_DIR}
-    CONFIGURE_COMMAND ""
-    BUILD_COMMAND ""
-    INSTALL_COMMAND ""
-    EXCLUDE_FROM_ALL TRUE
-    ${EXTERNALPROJECT_OPTIONS})
-else()
-  add_custom_target(lua_dev_deps)
-endif()
-
 if (CMAKE_SYSTEM_PROCESSOR MATCHES "arm|aarch")
   set(LUALS_ARCH arm64)
 else()

build.zig

@@ -545,8 +545,6 @@ pub fn build(b: *std.Build) !void {
 
     const gen_runtime = try runtime.nvim_gen_runtime(b, nlua0, funcs_data);
 
-    const lua_dev_deps = b.dependency("lua_dev_deps", .{});
-
     const test_deps = b.step("test_deps", "test prerequisites");
     test_deps.dependOn(&nvim_exe_install.step);
     // running tests doesn't require copying the static runtime, only the generated stuff
@@ -673,7 +671,6 @@ pub fn build(b: *std.Build) !void {
         b,
         nvim_exe,
         test_deps,
-        lua_dev_deps.path("."),
         test_config_step.getDirectory(),
         unit_headers,
     );
@@ -804,7 +801,7 @@ pub fn test_config(b: *std.Build) ![]u8 {
         \\M.test_source_path = "{[src_path]s}"
         \\M.test_lua_prg = ""
         \\M.test_luajit_prg = ""
-        \\ -- include path passed on the cmdline, see test/lua_runner.lua
+        \\ -- include path passed on the cmdline, see test/runner.lua
         \\M.include_paths = _G.c_include_path or {{}}
         \\
         \\return M

build.zig.zon

@@ -41,10 +41,6 @@
             .hash = "libiconv-1.18.0-p9sJwWnqAACzVYeWgXB5r5lOQ74XwTPlptixV0JPRO28",
             .lazy = true,
         },
-        .lua_dev_deps = .{
-            .url = "https://github.com/neovim/deps/raw/06ef2b58b0876f8de1a3f5a710473dcd7afff251/opt/lua-dev-deps.tar.gz",
-            .hash = "N-V-__8AAGevEQCHAkCozca5AIdN9DFc3Luf3g3r2AcbyOrm",
-        },
         .treesitter_c = .{
             .url = "git+https://github.com/tree-sitter/tree-sitter-c?ref=v0.24.1#7fa1be1b694b6e763686793d97da01f36a0e5c12",
             .hash = "N-V-__8AANxPSABzw3WBTSH_YkwaGAfrK6PBqAMqQedkDDim",

cmake.deps/deps.txt

@@ -51,6 +51,3 @@ WASMTIME_SHA256 c4a3c596a07c02ba6adce503154a2095fd98037a1e50d56add9773f0269ec9b7
 
 UNCRUSTIFY_URL https://github.com/uncrustify/uncrustify/archive/uncrustify-0.82.0.tar.gz
 UNCRUSTIFY_SHA256 e05f8d5ee36aaa1acfa032fe97546b7be46b1f4620e7c38037f8a42e25fe676f
-# This is where we get busted, luassert, ...
-LUA_DEV_DEPS_URL https://github.com/neovim/deps/raw/06ef2b58b0876f8de1a3f5a710473dcd7afff251/opt/lua-dev-deps.tar.gz
-LUA_DEV_DEPS_SHA256 49f8399e453103064a23c65534f266f3067cda716b6502f016bfafeed5799354

cmake/Deps.cmake

@@ -1,7 +1,6 @@
 set(DEPS_INSTALL_DIR "${CMAKE_BINARY_DIR}/usr")
 set(DEPS_BIN_DIR "${DEPS_INSTALL_DIR}/bin")
 set(DEPS_LIB_DIR "${DEPS_INSTALL_DIR}/lib")
-set(DEPS_SHARE_DIR "${DEPS_INSTALL_DIR}/share/lua/5.1")
 
 set(DEPS_BUILD_DIR "${CMAKE_BINARY_DIR}/build")
 set(DEPS_DOWNLOAD_DIR "${DEPS_BUILD_DIR}/downloads")

cmake/RunTests.cmake

@@ -60,18 +60,18 @@ if(IS_ABSOLUTE ${TEST_PATH})
   file(RELATIVE_PATH TEST_PATH "${ROOT_DIR}" "${TEST_PATH}")
 endif()
 
-separate_arguments(BUSTED_ARGS NATIVE_COMMAND $ENV{BUSTED_ARGS})
+separate_arguments(TEST_ARGS NATIVE_COMMAND $ENV{TEST_ARGS})
 
 if(DEFINED ENV{TEST_TAG} AND NOT "$ENV{TEST_TAG}" STREQUAL "")
-  list(APPEND BUSTED_ARGS --tags $ENV{TEST_TAG})
+  list(APPEND TEST_ARGS --tags $ENV{TEST_TAG})
 endif()
 
 if(DEFINED ENV{TEST_FILTER} AND NOT "$ENV{TEST_FILTER}" STREQUAL "")
-  list(APPEND BUSTED_ARGS --filter $ENV{TEST_FILTER})
+  list(APPEND TEST_ARGS --filter $ENV{TEST_FILTER})
 endif()
 
 if(DEFINED ENV{TEST_FILTER_OUT} AND NOT "$ENV{TEST_FILTER_OUT}" STREQUAL "")
-  list(APPEND BUSTED_ARGS --filter-out $ENV{TEST_FILTER_OUT})
+  list(APPEND TEST_ARGS --filter-out $ENV{TEST_FILTER_OUT})
 endif()
 
 # TMPDIR: for testutil.tmpname() and Nvim tempname().
@@ -95,14 +95,14 @@ endif()
 execute_process(
   # Note: because of "-ll" (low-level interpreter mode), some modules like
   # _core/editor.lua are not loaded.
-  COMMAND ${NVIM_PRG} -ll ${ROOT_DIR}/test/lua_runner.lua ${DEPS_INSTALL_DIR}/share/lua/5.1/ busted -v -o test.busted.outputHandlers.nvim
+  COMMAND ${NVIM_PRG} -ll ${ROOT_DIR}/test/runner.lua -v
-    -Xoutput "{\"test_path\": \"${TEST_PATH}\", \"summary_file\": \"${TEST_SUMMARY_FILE}\"}"
+    --summary-file=${TEST_SUMMARY_FILE}
-    --lazy --helper=${TEST_DIR}/${TEST_TYPE}/preload.lua
+    --helper=${TEST_DIR}/${TEST_TYPE}/preload.lua
     --lpath=${BUILD_DIR}/?.lua
     --lpath=${ROOT_DIR}/src/?.lua
     --lpath=${ROOT_DIR}/runtime/lua/?.lua
     --lpath=?.lua
-    ${BUSTED_ARGS}
+    ${TEST_ARGS}
     ${TEST_PATH}
   TIMEOUT $ENV{TEST_TIMEOUT}
   WORKING_DIRECTORY ${TEST_XDG_PREFIX}

contrib/local.mk.example

@@ -41,7 +41,6 @@
 # Uncomment these entries to instead use system-wide installations of
 # them.
 #
-# DEPS_CMAKE_FLAGS += -DUSE_BUNDLED_BUSTED=OFF
 # DEPS_CMAKE_FLAGS += -DUSE_BUNDLED_GETTEXT=OFF
 # DEPS_CMAKE_FLAGS += -DUSE_BUNDLED_LIBICONV=OFF
 # DEPS_CMAKE_FLAGS += -DUSE_BUNDLED_LIBUV=OFF

runtime/doc/dev_test.txt

@@ -37,12 +37,25 @@ You can learn [Lua concepts 15 minutes](https://learnxinyminutes.com/docs/lua/),
 see also |lua-guide|. Use any existing test as a template to start writing new
 tests, or see |dev-quickstart|.
 
-Tests are run by the `/cmake/RunTests.cmake` script using `busted` (a Lua test-runner).
+Tests are run by the `/cmake/RunTests.cmake` script using the repo-local Lua
+test harness in `/test/harness.lua`.
 For some failures, `./build/nvim.log` (or `$NVIM_LOG_FILE`) may provide insight.
 
 Depending on the presence of binaries (e.g., `xclip`) some tests will be
 skipped.
 
+Harness isolation                                  *dev-test-harness-isolation*
+
+The Lua harness runs all selected spec files in one low-level `nvim -ll`
+process, then restores a baseline before each file. For each suite iteration,
+the file boundary baseline is captured after `--helper` is loaded, so
+helper-provided modules and defaults persist across files.
+Helper files are preload-only: they may require modules, set defaults, and
+register suite-end cleanup, but they do not define tests or hooks.
+
+The harness restores `_G`, `package.loaded`, `package.preload`, `arg`, and the
+process environment with the same shallow file boundary model that busted uses.
+
 ==============================================================================
 Test Layout
 
@@ -56,7 +69,8 @@ Test Layout
 - `/test/includes` : include-files for use by luajit `ffi.cdef` C definitions
   parser: normally used to make macros not accessible via this mechanism
   accessible the other way.
-- `/test/*/preload.lua` : modules preloaded by busted `--helper` option
+- `/test/*/preload.lua` : modules and defaults preloaded by the harness
+  `--helper` option
 - `/test/**/testutil.lua` : common utility functions in the context of the test
   runner
 - `/test/**/testnvim.lua` : common utility functions in the context of the
@@ -145,9 +159,7 @@ need to install and configure:
 2. [local-lua-debugger-vscode](https://github.com/mfussenegger/nvim-dap/wiki/Debug-Adapter-installation#local-lua-debugger-vscode)
 3. [nlua](https://github.com/mfussenegger/nlua)
 4. [one-small-step-for-vimkind](https://github.com/jbyuki/one-small-step-for-vimkind) (called `osv`)
-5. A `nbusted` command in `$PATH`. This command can be a copy of `busted` with
+5. An `nlua` command in `$PATH`.
-   `exec '/usr/bin/lua5.1'"` replaced with `"exec '/usr/bin/nlua'"` (or the
-   path to your `nlua`)
 
 
 The setup roughly looks like this: >
@@ -163,7 +175,7 @@ The setup roughly looks like this: >
               │                     │
               ▼                     │
          ┌─────────┐                │
-         │ nbusted │                │
+         │   nlua  │                │
          └─────────┘                │
               │                     │
               ▼                     │
@@ -206,11 +218,11 @@ With these installed you can use a configuration like this: >
       request = "launch",
       cwd = "${workspaceFolder}",
       program = {
-        command = "nbusted",
+        command = "nlua",
       },
       args = {
-        "--ignore-lua",
+        "-ll",
-        "--lazy",
+        "test/runner.lua",
         "--helper=test/functional/preload.lua",
         "--lpath=build/?.lua",
         "--lpath=?.lua",
@@ -274,7 +286,7 @@ Limitations:
     if os.getenv("LOCAL_LUA_DEBUGGER_VSCODE") == "1" then
       require("lldebugger").start()
     end
-<  This is a [local-lua-debugger limitation](https://github.com/tomblind/local-lua-debugger-vscode?tab=readme-ov-file#busted)
+<  This is a local-lua-debugger limitation.
 - You cannot step into code of files which get baked into the nvim binary
   (such as `_core/*.lua` and `inspect.lua`).
 
@@ -314,10 +326,10 @@ or >
     cmake -E env "TEST_FILE=test/functional/foo.lua" cmake --build build --target functionaltest
 
 To _repeat_ a test: >
-    BUSTED_ARGS="--repeat=100 --no-keep-going" TEST_FILE=test/functional/foo_spec.lua make functionaltest
+    TEST_ARGS="--repeat=100 --no-keep-going" TEST_FILE=test/functional/foo_spec.lua make functionaltest
 
 or >
-    cmake -E env "TEST_FILE=test/functional/foo_spec.lua" cmake -E env BUSTED_ARGS="--repeat=100 --no-keep-going" cmake --build build --target functionaltest
+    cmake -E env "TEST_FILE=test/functional/foo_spec.lua" cmake -E env TEST_ARGS="--repeat=100 --no-keep-going" cmake --build build --target functionaltest
 
 FILTER BY TAG
 
@@ -430,7 +442,7 @@ Test behaviour is affected by environment variables. Currently supported
 treated as Integer; when defined, treated as String; when defined, treated as
 Number; !must be defined to function properly):
 
-- `BUSTED_ARGS` (F) (U): arguments forwarded to `busted`.
+- `TEST_ARGS` (F) (U): arguments forwarded to the local test harness.
 
 - `CC` (U) (S): specifies which C compiler to use to preprocess files.
   Currently only compilers with gcc-compatible arguments are supported.

runtime/doc/dev_tools.txt

@@ -388,7 +388,7 @@ Gdb                                                          *dev-tools-gdb*
 
 USING GDB TO STEP THROUGH FUNCTIONAL TESTS
 
-Use `TEST_TAG` to run tests matching busted tags (of the form `#foo` e.g.
+Use `TEST_TAG` to run tests matching `#foo` tags (e.g.
 `it("test #foo ...", ...)`):
 >bash
     GDB=1 TEST_TAG=foo make functionaltest
@@ -403,7 +403,7 @@ Then, in another terminal:
 USING LLDB TO STEP THROUGH UNIT TESTS
 
 >
-    lldb .deps/usr/bin/luajit -- .deps/usr/bin/busted --lpath="./build/?.lua" test/unit/
+    lldb build/bin/nvim -- -ll test/runner.lua --lpath=./build/?.lua test/unit/
 <
 USING GDB
 

runtime/lua/vim/_core/shared.lua

@@ -64,6 +64,31 @@ function vim.deepcopy(orig, noref)
   return deepcopy(orig, not noref and {} or nil)
 end
 
+--- Returns a shallow copy of `orig`.
+---
+--- Non-table values are returned as-is. Table keys and values are copied by
+--- reference, and the original metatable is preserved. Use |vim.deepcopy()|
+--- for a recursive copy.
+---
+--- @nodoc
+--- @generic T
+--- @param orig T
+--- @return T
+function vim._copy(orig)
+  if type(orig) ~= 'table' then
+    return orig
+  end
+
+  --- @cast orig table<any,any>
+
+  local copy = {} --- @type table<any,any>
+  for k, v in pairs(orig) do
+    copy[k] = v
+  end
+
+  return setmetatable(copy, getmetatable(orig))
+end
+
 --- @class vim.gsplit.Opts
 --- @inlinedoc
 ---
@@ -678,6 +703,8 @@ local function deep_equal(left, right, seen)
     return false
   end
 
+  ---@cast left table<any, any>
+  ---@cast right table<any, any>
   seen = seen or {}
   local seen_left = seen[left]
   if seen_left and seen_left[right] ~= nil then

test/.emmyrc.json

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://raw.githubusercontent.com/EmmyLuaLs/emmylua-analyzer-rust/refs/heads/main/crates/emmylua_code_analysis/resources/schema.json",
+  "format": {
+    "externalTool": {
+      "program": "stylua",
+      "args": [
+        "-",
+        "--stdin-filepath",
+        "${file}"
+      ]
+    }
+  },
+  "diagnostics": {
+    "disable": [
+      "unnecessary-if"
+    ]
+  },
+  "codeAction": {
+    "insertSpace": true
+  },
+  "strict": {
+    "typeCall": true,
+    "arrayIndex": true
+  }
+}

test/.luarc.json

@@ -6,12 +6,7 @@
   "workspace": {
     "library": [
       "../runtime/lua",
-      "../src",
+      "../src"
-      "../build/usr/share/lua/5.1",
-      "../build",
-      "${3rd}/busted/library",
-      "${3rd}/luassert/library",
-      "${3rd}/luv/library"
     ],
     "checkThirdParty": "Disable"
   },

test/CMakeLists.txt

@@ -7,7 +7,6 @@ set(TEST_OPTIONS
       -D BUILD_DIR=${CMAKE_BINARY_DIR}
       -D CIRRUS_CI=$ENV{CIRRUS_CI}
       -D CI_BUILD=${CI_BUILD}
-      -D DEPS_INSTALL_DIR=${DEPS_INSTALL_DIR}
       -D NVIM_PRG=$<TARGET_FILE:nvim_bin>
       -D TEST_DIR=${TEST_DIR}
       -D ROOT_DIR=${PROJECT_SOURCE_DIR})
@@ -20,7 +19,7 @@ if(LUA_HAS_FFI)
       ${TEST_OPTIONS}
       -P ${PROJECT_SOURCE_DIR}/cmake/RunTests.cmake
     USES_TERMINAL)
-  add_dependencies(unittest lua_dev_deps nvim)
+  add_dependencies(unittest nvim)
 else()
   message(WARNING "disabling unit tests: no Luajit FFI in ${LUA_PRG}")
 endif()
@@ -36,7 +35,7 @@ add_custom_target(benchmark
     -P ${PROJECT_SOURCE_DIR}/cmake/RunTests.cmake
   DEPENDS tty-test
   USES_TERMINAL)
-add_dependencies(benchmark lua_dev_deps nvim)
+add_dependencies(benchmark nvim)
 
 add_custom_target(functionaltest
   COMMAND ${CMAKE_COMMAND}
@@ -45,7 +44,7 @@ add_custom_target(functionaltest
     -P ${PROJECT_SOURCE_DIR}/cmake/RunTests.cmake
   DEPENDS printenv-test printargs-test shell-test pwsh-test streams-test tty-test
   USES_TERMINAL)
-add_dependencies(functionaltest lua_dev_deps nvim)
+add_dependencies(functionaltest nvim)
 
 # Create multiple targets for groups of functional tests to enable parallel testing.
 set(group_targets "")
@@ -66,7 +65,7 @@ foreach(test_file ${test_files})
         ${TEST_OPTIONS}
         -P ${PROJECT_SOURCE_DIR}/cmake/RunTests.cmake
       DEPENDS printenv-test printargs-test shell-test pwsh-test streams-test tty-test)
-    add_dependencies(${group_target} lua_dev_deps nvim)
+    add_dependencies(${group_target} nvim)
     list(APPEND group_targets ${group_target})
     list(APPEND summary_files ${summary_file})
   endif()

test/_meta.lua

@@ -1,10 +1,25 @@
 --- @meta
 
-do -- Mark block as optional
+--- @param name string
-  ---Mark a test as placeholder.
+--- @param fn? fun()
-  ---
+function it(name, fn) end
-  ---This will not fail or pass, it will simply be marked as "pending".
+
-  ---@param name string
+--- @param name string
-  ---@param block? fun()
+--- @param fn fun()
-  function pending(name, block) end
+function describe(name, fn) end
-end
+
+--- @param name? string
+--- @param block? fun()|string
+function pending(name, block) end
+
+--- @param fn fun()
+function setup(fn) end
+
+--- @param fn fun()
+function before_each(fn) end
+
+--- @param fn fun()
+function after_each(fn) end
+
+--- @param fn fun()
+function teardown(fn) end

test/assert.lua

@@ -0,0 +1,102 @@
+--- @class test.assert
+local M = {}
+
+local FORMAT_DEPTH = 100
+
+--- @param value any
+--- @return string
+local function format_value(value)
+  if type(value) == 'string' then
+    return string.format('%q', value)
+  end
+
+  local ok, inspected = pcall(vim.inspect, value, { depth = FORMAT_DEPTH })
+  if ok then
+    return inspected
+  end
+
+  return tostring(value)
+end
+
+--- @param condition boolean
+--- @param value any
+--- @param context any
+--- @param fallback string
+local function assert_value(condition, value, context, fallback)
+  if not condition then
+    local message = context ~= nil and tostring(context) or fallback
+    error(message, 0)
+  end
+  return value
+end
+
+--- @param expected any
+--- @param actual any
+--- @param comparator string
+--- @return string
+local function comparison_message(expected, actual, comparator)
+  return ('Expected values to be %s.\nExpected:\n%s\nActual:\n%s'):format(
+    comparator,
+    format_value(expected),
+    format_value(actual)
+  )
+end
+
+--- @param expected any
+--- @param actual any
+--- @param context? any
+--- @return any
+function M.eq(expected, actual, context)
+  return assert_value(
+    vim.deep_equal(expected, actual),
+    actual,
+    context,
+    comparison_message(expected, actual, 'equal')
+  )
+end
+
+--- @param expected any
+--- @param actual any
+--- @param context? any
+--- @return any
+function M.neq(expected, actual, context)
+  return assert_value(
+    not vim.deep_equal(expected, actual),
+    actual,
+    context,
+    ('Expected values to differ.\nValue:\n%s'):format(format_value(actual))
+  )
+end
+
+--- @param value any
+--- @param context? any
+--- @return any
+function M.is_true(value, context)
+  return M.eq(true, value, context)
+end
+
+--- @param value any
+--- @param context? any
+--- @return any
+function M.is_false(value, context)
+  return M.eq(false, value, context)
+end
+
+-- TODO(lewis6991): remove these aliases
+M.True = M.is_true
+M.False = M.is_false
+M.equals = M.eq
+M.Equal = M.eq
+
+return setmetatable(M, {
+  --- @param condition any
+  --- @param message? string
+  --- @param level? integer
+  __call = function(_, condition, message, level, ...)
+    if condition then
+      return condition, message, level, ...
+    end
+
+    error(message or 'assertion failed!', (type(level) == 'number' and level or 1) + 1)
+  end,
+})

test/benchmark/preload.lua

@@ -1,4 +1,4 @@
--- Modules loaded here will not be cleared and reloaded by Busted.
+-- Modules loaded here will not be cleared and reloaded by the local harness.
--- Busted started doing this to help provide more isolation.  See issue #62
+-- Keeping these preloaded preserves cross-file setup while still resetting
--- for more information about this.
+-- non-helper modules between files.
 require('test.functional.testnvim')()

test/busted/outputHandlers/TAP.lua

@@ -1,16 +0,0 @@
--- Extends the upstream TAP handler, to display the log with suiteEnd.
-
-local t_global = require('test.testutil')
-
-return function(options)
-  local busted = require 'busted'
-  local handler = require 'busted.outputHandlers.TAP'(options)
-
-  local suiteEnd = function()
-    io.write(t_global.read_nvim_log(nil, true))
-    return nil, true
-  end
-  busted.subscribe({ 'suite', 'end' }, suiteEnd)
-
-  return handler
-end

test/busted/outputHandlers/nvim.lua

@@ -1,359 +0,0 @@
-local pretty = require 'pl.pretty'
-local t_global = require('test.testutil')
-
-local colors = setmetatable({}, {
-  __index = function()
-    return function(s)
-      return s == nil and '' or tostring(s)
-    end
-  end,
-})
-
-local enable_colors = true
-if os.getenv 'TEST_COLORS' then
-  local test_colors = os.getenv('TEST_COLORS'):lower()
-  local disable_colors = test_colors == 'false'
-    or test_colors == '0'
-    or test_colors == 'no'
-    or test_colors == 'off'
-  enable_colors = not disable_colors
-end
-if enable_colors then
-  colors = require 'term.colors'
-end
-
-return function(options)
-  local busted = require 'busted'
-  local handler = require 'busted.outputHandlers.base'()
-  local args = options.arguments
-  args = vim.json.decode(#args > 0 and table.concat(args, ',') or '{}')
-
-  local c = {
-    succ = function(s)
-      return colors.bright(colors.green(s))
-    end,
-    skip = function(s)
-      return colors.bright(colors.yellow(s))
-    end,
-    fail = function(s)
-      return colors.bright(colors.magenta(s))
-    end,
-    errr = function(s)
-      return colors.bright(colors.red(s))
-    end,
-    test = tostring,
-    file = colors.cyan,
-    time = colors.dim,
-    note = colors.yellow,
-    sect = function(s)
-      return colors.green(colors.dim(s))
-    end,
-    nmbr = colors.bright,
-  }
-
-  local repeatSuiteString = '\nRepeating all tests (run %d of %d) . . .\n\n'
-  local randomizeString = c.note('Note: Randomizing test order with a seed of %d.\n')
-  local globalSetup = c.sect('--------') .. ' Global test environment setup.\n'
-  local fileStartString = c.sect('--------') .. ' Running tests from ' .. c.file('%s') .. '\n'
-  local runString = c.sect('RUN     ') .. ' ' .. c.test('%s') .. ': '
-  local successString = c.succ('OK') .. '\n'
-  local skippedString = c.skip('SKIP') .. '\n'
-  local failureString = c.fail('FAIL') .. '\n'
-  local errorString = c.errr('ERR') .. '\n'
-  local fileEndString = c.sect('--------')
-    .. ' '
-    .. c.nmbr('%d')
-    .. ' %s from '
-    .. c.file('%s')
-    .. ' '
-    .. c.time('(%.2f ms total)')
-    .. '\n\n'
-  local globalTeardown = c.sect('--------') .. ' Global test environment teardown.\n'
-  local suiteEndString = c.sect('========')
-    .. ' '
-    .. c.nmbr('%d')
-    .. ' %s from '
-    .. c.nmbr('%d')
-    .. ' test %s ran. '
-    .. c.time('(%.2f ms total)')
-    .. '\n'
-  local successStatus = c.succ('PASSED  ') .. ' ' .. c.nmbr('%d') .. ' %s.\n'
-  local timeString = c.time('%.2f ms')
-
-  local summaryStrings = {
-    skipped = {
-      header = c.skip('SKIPPED ') .. ' ' .. c.nmbr('%d') .. ' %s, listed below:\n',
-      test = c.skip('SKIPPED ') .. ' %s\n',
-      footer = ' ' .. c.nmbr('%d') .. ' SKIPPED %s\n',
-    },
-
-    failure = {
-      header = c.fail('FAILED  ') .. ' ' .. c.nmbr('%d') .. ' %s, listed below:\n',
-      test = c.fail('FAILED  ') .. ' %s\n',
-      footer = ' ' .. c.nmbr('%d') .. ' FAILED %s\n',
-    },
-
-    error = {
-      header = c.errr('ERROR   ') .. ' ' .. c.nmbr('%d') .. ' %s, listed below:\n',
-      test = c.errr('ERROR   ') .. ' %s\n',
-      footer = ' ' .. c.nmbr('%d') .. ' %s\n',
-    },
-  }
-
-  local fileCount = 0
-  local fileTestCount = 0
-  local testCount = 0
-  local successCount = 0
-  local skippedCount = 0
-  local failureCount = 0
-  local errorCount = 0
-
-  local naCheck = function(pending)
-    if vim.list_contains(vim.split(pending.name, '[ :]'), 'N/A') then
-      return true
-    end
-    if type(pending.message) ~= 'string' then
-      return false
-    end
-    if vim.list_contains(vim.split(pending.message, '[ :]'), 'N/A') then
-      return true
-    end
-    return false
-  end
-
-  local pendingDescription = function(pending)
-    local string = ''
-
-    if type(pending.message) == 'string' then
-      string = string .. pending.message .. '\n'
-    elseif pending.message ~= nil then
-      string = string .. pretty.write(pending.message) .. '\n'
-    end
-
-    return string
-  end
-
-  local failureDescription = function(failure)
-    local string = failure.randomseed and ('Random seed: ' .. failure.randomseed .. '\n') or ''
-    if type(failure.message) == 'string' then
-      string = string .. failure.message
-    elseif failure.message == nil then
-      string = string .. 'Nil error'
-    else
-      string = string .. pretty.write(failure.message)
-    end
-
-    string = string .. '\n'
-
-    if options.verbose and failure.trace and failure.trace.traceback then
-      string = string .. failure.trace.traceback .. '\n'
-    end
-
-    return string
-  end
-
-  local getFileLine = function(element)
-    local fileline = ''
-    if element.trace or element.trace.short_src then
-      local fname = vim.fs.normalize(element.trace.short_src)
-      fileline = colors.cyan(fname) .. ' @ ' .. colors.cyan(element.trace.currentline) .. ': '
-    end
-    return fileline
-  end
-
-  local getTestList = function(status, count, list, getDescription)
-    local string = ''
-    local header = summaryStrings[status].header
-    if count > 0 and header then
-      local tests = (count == 1 and 'test' or 'tests')
-      local errors = (count == 1 and 'error' or 'errors')
-      string = header:format(count, status == 'error' and errors or tests)
-
-      local testString = summaryStrings[status].test
-      if testString then
-        local naCount = 0
-        for _, t in ipairs(list) do
-          if status == 'skipped' and naCheck(t) then
-            naCount = naCount + 1
-          else
-            local fullname = getFileLine(t.element) .. colors.bright(t.name)
-            string = string .. testString:format(fullname)
-            string = string .. getDescription(t)
-          end
-        end
-        if naCount > 0 then
-          string = string
-            .. colors.bright(
-              ('%d N/A %s not shown\n'):format(naCount, naCount == 1 and 'test' or 'tests')
-            )
-        end
-      end
-    end
-    return string
-  end
-
-  local getSummary = function(status, count)
-    local string = ''
-    local footer = summaryStrings[status].footer
-    if count > 0 and footer then
-      local tests = (count == 1 and 'TEST' or 'TESTS')
-      local errors = (count == 1 and 'ERROR' or 'ERRORS')
-      string = footer:format(count, status == 'error' and errors or tests)
-    end
-    return string
-  end
-
-  local getSummaryString = function()
-    local tests = (successCount == 1 and 'test' or 'tests')
-    local string = successStatus:format(successCount, tests)
-
-    string = string .. getTestList('skipped', skippedCount, handler.pendings, pendingDescription)
-    string = string .. getTestList('failure', failureCount, handler.failures, failureDescription)
-    string = string .. getTestList('error', errorCount, handler.errors, failureDescription)
-
-    string = string .. ((skippedCount + failureCount + errorCount) > 0 and '\n' or '')
-    string = string .. getSummary('skipped', skippedCount)
-    string = string .. getSummary('failure', failureCount)
-    string = string .. getSummary('error', errorCount)
-
-    return string
-  end
-
-  handler.suiteReset = function()
-    fileCount = 0
-    fileTestCount = 0
-    testCount = 0
-    successCount = 0
-    skippedCount = 0
-    failureCount = 0
-    errorCount = 0
-
-    return nil, true
-  end
-
-  handler.suiteStart = function(_suite, count, total, randomseed)
-    if total > 1 then
-      io.write(repeatSuiteString:format(count, total))
-    end
-    if randomseed then
-      io.write(randomizeString:format(randomseed))
-    end
-    io.write(globalSetup)
-    io.flush()
-
-    return nil, true
-  end
-
-  local function getElapsedTime(tbl)
-    if tbl.duration then
-      return tbl.duration * 1000
-    else
-      return tonumber('nan')
-    end
-  end
-
-  handler.suiteEnd = function(suite, _count, _total)
-    local elapsedTime_ms = getElapsedTime(suite)
-    local tests = (testCount == 1 and 'test' or 'tests')
-    local files = (fileCount == 1 and 'file' or 'files')
-    if type(args.test_path) == 'string' then
-      files = files .. ' of ' .. args.test_path
-    end
-    local sf = type(args.summary_file) == 'string'
-        and args.summary_file ~= '-'
-        and io.open(args.summary_file, 'w')
-      or io.stdout
-    io.write(globalTeardown)
-    io.flush()
-    sf:write('\n')
-    sf:write(suiteEndString:format(testCount, tests, fileCount, files, elapsedTime_ms))
-    sf:write(getSummaryString())
-    if failureCount > 0 or errorCount > 0 then
-      sf:write(t_global.read_nvim_log(nil, true))
-    end
-    sf:flush()
-    if sf ~= io.stdout then
-      sf:close()
-    end
-
-    return nil, true
-  end
-
-  handler.fileStart = function(file)
-    fileTestCount = 0
-    io.write(fileStartString:format(vim.fs.normalize(file.name)))
-    io.flush()
-    return nil, true
-  end
-
-  handler.fileEnd = function(file)
-    local elapsedTime_ms = getElapsedTime(file)
-    local tests = (fileTestCount == 1 and 'test' or 'tests')
-    fileCount = fileCount + 1
-    io.write(
-      fileEndString:format(fileTestCount, tests, vim.fs.normalize(file.name), elapsedTime_ms)
-    )
-    io.flush()
-    return nil, true
-  end
-
-  handler.testStart = function(element, _parent)
-    local testid = _G._nvim_test_id or ''
-    local desc = ('%s %s'):format(testid, handler.getFullName(element))
-    io.write(runString:format(desc))
-    io.flush()
-
-    return nil, true
-  end
-
-  local function write_status(element, string)
-    io.write(timeString:format(getElapsedTime(element)) .. ' ' .. string)
-    io.flush()
-  end
-
-  handler.testEnd = function(element, _parent, status, _debug)
-    local string
-
-    fileTestCount = fileTestCount + 1
-    testCount = testCount + 1
-    if status == 'success' then
-      successCount = successCount + 1
-      string = successString
-    elseif status == 'pending' then
-      skippedCount = skippedCount + 1
-      string = skippedString
-    elseif status == 'failure' then
-      failureCount = failureCount + 1
-      string = failureString .. failureDescription(handler.failures[#handler.failures])
-    elseif status == 'error' then
-      errorCount = errorCount + 1
-      string = errorString .. failureDescription(handler.errors[#handler.errors])
-    else
-      string = 'unexpected test status! (' .. status .. ')'
-    end
-    write_status(element, string)
-
-    return nil, true
-  end
-
-  handler.error = function(element, _parent, _message, _debug)
-    if element.descriptor ~= 'it' then
-      write_status(element, failureDescription(handler.errors[#handler.errors]))
-      errorCount = errorCount + 1
-    end
-
-    return nil, true
-  end
-
-  busted.subscribe({ 'suite', 'reset' }, handler.suiteReset)
-  busted.subscribe({ 'suite', 'start' }, handler.suiteStart)
-  busted.subscribe({ 'suite', 'end' }, handler.suiteEnd)
-  busted.subscribe({ 'file', 'start' }, handler.fileStart)
-  busted.subscribe({ 'file', 'end' }, handler.fileEnd)
-  busted.subscribe({ 'test', 'start' }, handler.testStart, { predicate = handler.cancelOnPending })
-  busted.subscribe({ 'test', 'end' }, handler.testEnd, { predicate = handler.cancelOnPending })
-  busted.subscribe({ 'failure' }, handler.error)
-  busted.subscribe({ 'error' }, handler.error)
-
-  return handler
-end

test/format_string.lua

@@ -1,5 +1,3 @@
-local luaassert = require('luassert')
-
 local M = {}
 
 local SUBTBL = {
@@ -124,7 +122,7 @@ function M.format_luav(v, indent, opts)
   else
     print(type(v))
     -- Not implemented yet
-    luaassert(false)
+    assert(false)
   end
   return ret
 end

test/functional/autocmd/filetype_spec.lua

@@ -12,6 +12,6 @@ describe('autocmd FileType', function()
     command('let g:foo = 0')
     command('autocmd FileType help let g:foo = g:foo + 1')
     command('help help')
-    assert.same(1, eval('g:foo'))
+    assert.eq(1, eval('g:foo'))
   end)
 end)

test/functional/harness/assert_spec.lua

@@ -0,0 +1,28 @@
+local assert = require('test.assert')
+
+describe('test.assert', function()
+  it('ignores aliasing differences', function()
+    local shared = {}
+
+    assert.eq({ 1, shared, 1, shared }, { 1, {}, 1, {} })
+    assert.eq({ 1, {}, 1, {} }, { 1, shared, 1, shared })
+  end)
+
+  it('handles cyclic tables', function()
+    local expected = {}
+    local actual = {}
+
+    expected[1] = expected
+    actual[1] = actual
+
+    assert.eq(expected, actual)
+  end)
+
+  it('still rejects different structures', function()
+    local expected = {}
+
+    expected[1] = expected
+
+    assert.neq(expected, { {} })
+  end)
+end)

test/functional/lua/buffer_updates_spec.lua

@@ -8,7 +8,6 @@ local api = n.api
 local fn = n.fn
 local clear = n.clear
 local eq = t.eq
-local fail = t.fail
 local exec_lua = n.exec_lua
 local feed = n.feed
 local expect_events = t.expect_events
@@ -507,7 +506,7 @@ describe('lua: nvim_buf_attach on_bytes', function()
       for _, event in ipairs(events) do
         for _, elem in ipairs(event) do
           if type(elem) == 'number' and elem < 0 then
-            fail(string.format('Received event has negative values'))
+            error('Received event has negative values')
           end
         end
 

test/functional/lua/net_spec.lua

@@ -199,7 +199,7 @@ describe('vim.net.request', function()
       return result
     ]])
 
-    assert.is_table(headers)
+    t.eq('table', type(headers), 'Expected headers to be a table')
     -- httpbingo.org/request returns each header as a list in the returned value
     t.eq(headers.Authorization[1], 'Bearer test-token', 'Expected Authorization header')
     t.eq(headers['X-Custom-Header'][1], 'custom-value', 'Expected X-Custom-Header')

test/functional/lua/vim_spec.lua

@@ -834,6 +834,26 @@ describe('lua stdlib', function()
     )
   end)
 
+  it('vim._copy', function()
+    ok(exec_lua([[
+      local inner = { x = 1 }
+      local mt = { tag = true }
+      local a = setmetatable({ inner = inner }, mt)
+      local b = vim._copy(a)
+
+      local c = vim.empty_dict()
+      c.inner = inner
+      local d = vim._copy(c)
+
+      return b ~= a
+        and b.inner == inner
+        and getmetatable(b) == mt
+        and d ~= c
+        and d.inner == inner
+        and not vim.islist(d)
+    ]]))
+  end)
+
   it('vim.pesc', function()
     eq('foo%-bar', exec_lua([[return vim.pesc('foo-bar')]]))
     eq('foo%%%-bar', exec_lua([[return vim.pesc(vim.pesc('foo-bar'))]]))
@@ -1249,7 +1269,11 @@ describe('lua stdlib', function()
     eq(true, exec_lua [[ return vim.deep_equal({a={b=1}}, {a={b=1}}) ]])
     eq(true, exec_lua [[ return vim.deep_equal({a={b={nil}}}, {a={b={}}}) ]])
     eq(true, exec_lua [[ return vim.deep_equal({a=1, [5]=5}, {nil,nil,nil,nil,5,a=1}) ]])
-    eq(true, exec_lua [[ local shared = {}; return vim.deep_equal({ 1, shared, 1, shared }, { 1, {}, 1, {} }) ]])
+    eq(
+      true,
+      exec_lua [[ local shared = {}; return vim.deep_equal({ 1, shared, 1, shared }, { 1, {}, 1, {} }) ]]
+    )
+    -- cyclic table
     eq(true, exec_lua [[ local a,b={},{}; a[1]=a; b[1]=b; return vim.deep_equal(a, b) ]])
     eq(false, exec_lua [[ return vim.deep_equal(1, {nil,nil,nil,nil,5,a=1}) ]])
     eq(false, exec_lua [[ return vim.deep_equal(1, 3) ]])

test/functional/preload.lua

@@ -1,6 +1,6 @@
--- Modules loaded here will NOT be cleared and reloaded by Busted.
+-- Modules loaded here will not be cleared and reloaded by the local harness.
--- Busted started doing this to help provide more isolation.  See issue #62
+-- Keeping these preloaded preserves cross-file setup while still resetting
--- for more information about this.
+-- non-helper modules between files.
 local t = require('test.testutil')
 require('test.functional.testnvim')()
 require('test.functional.ui.screen')

test/functional/terminal/parser_spec.lua

@@ -80,14 +80,14 @@ describe(':terminal', function()
 
     send_osc_with_terminator(BEL)
     --- @type string
-    assert.same(
+    assert.eq(
       { sequence = OSC_PREFIX .. '10;?', terminator = BEL },
       exec_lua([[return _G.osc10_response]])
     )
 
     send_osc_with_terminator(ST)
     --- @type string
-    assert.same(
+    assert.eq(
       { sequence = OSC_PREFIX .. '10;?', terminator = ST },
       exec_lua([[return _G.osc10_response]])
     )

test/functional/testnvim.lua

@@ -1,6 +1,7 @@
 local uv = vim.uv
 local t = require('test.testutil')
-local busted = require('busted')
+---@type test.harness
+local harness = require('test.harness')
 
 local Session = require('test.client.session')
 local uv_stream = require('test.client.uv_stream')
@@ -528,7 +529,7 @@ function M.new_session(keep, ...)
   return new_session
 end
 
-busted.subscribe({ 'suite', 'end' }, function()
+harness.on_suite_end(function()
   M.check_close(true)
   local timed_out = false
   local timer = assert(vim.uv.new_timer())

test/functional/ui/screen.lua

@@ -47,7 +47,6 @@
 
 local t = require('test.testutil')
 local n = require('test.functional.testnvim')()
-local busted = require('busted')
 local uv = vim.uv
 
 local deepcopy = vim.deepcopy
@@ -911,7 +910,7 @@ between asynchronous (feed(), nvim_input()) and synchronous API calls.
     if eof then
       err = err .. '\n\n' .. eof[2]
     end
-    busted.fail(err .. '\n\nSnapshot:\n' .. self:_print_snapshot(), 3)
+    error(err .. '\n\nSnapshot:\n' .. self:_print_snapshot(), 3)
   elseif did_warn then
     if eof then
       print(eof[2])
@@ -922,9 +921,9 @@ between asynchronous (feed(), nvim_input()) and synchronous API calls.
   end
 
   if flags.intermediate and not intermediate_seen then
-    busted.fail('Expected intermediate screen state before final screen state', 3)
+    error('Expected intermediate screen state before final screen state', 3)
   elseif flags.unchanged and intermediate_seen then
-    busted.fail(
+    error(
       'Expected screen state to be unchanged.\nIntermediate screen state:\n'
         .. intermediate_state_snapshot,
       3

test/lua_runner.lua

@@ -1,91 +0,0 @@
-local platform = vim.uv.os_uname()
-local deps_install_dir = table.remove(_G.arg, 1)
-_G.c_include_path = {}
-while vim.startswith(_G.arg[1], '-I') do
-  table.insert(_G.c_include_path, string.sub(table.remove(_G.arg, 1), 3))
-end
-local subcommand = table.remove(_G.arg, 1)
-local suffix = (platform and platform.sysname:lower():find 'windows') and '.dll' or '.so'
-package.path = (deps_install_dir .. '/?.lua;')
-  .. (deps_install_dir .. '/?/init.lua;')
-  .. package.path
-package.cpath = deps_install_dir .. '/?' .. suffix .. ';' .. package.cpath
-
-local uv = vim.uv
-
--- we use busted and luacheck and their lua dependencies
--- But installing their binary dependencies with luarocks is very
--- slow, replace them with vim.uv wrappers
-
-local system = {}
-package.loaded['system.core'] = system
-function system.monotime()
-  uv.update_time()
-  return uv.now() * 1e-3
-end
-function system.gettime()
-  local sec, usec = uv.gettimeofday()
-  return sec + usec * 1e-6
-end
-function system.sleep(sec)
-  uv.sleep(sec * 1e3)
-end
-
-local term = {}
-package.loaded['term.core'] = term
-function term.isatty(_)
-  return uv.guess_handle(1) == 'tty'
-end
-
-local lfs = { _VERSION = 'fake' }
-package.loaded['lfs'] = lfs
-
-function lfs.attributes(path, attr)
-  local stat = uv.fs_stat(path)
-  if attr == 'mode' then
-    return stat and stat.type or ''
-  elseif attr == 'modification' then
-    if not stat then
-      return nil
-    end
-    local mtime = stat.mtime
-    return mtime.sec + mtime.nsec * 1e-9
-  else
-    error('not implemented')
-  end
-end
-
-function lfs.currentdir()
-  return uv.cwd()
-end
-
-function lfs.chdir(dir)
-  local status, err = pcall(uv.chdir, dir)
-  if status then
-    return true
-  else
-    return nil, err
-  end
-end
-
-function lfs.dir(path)
-  local fs = uv.fs_scandir(path)
-  return function()
-    if not fs then
-      return
-    end
-    return uv.fs_scandir_next(fs)
-  end
-end
-
-function lfs.mkdir(dir)
-  return uv.fs_mkdir(dir, 493) -- octal 755
-end
-
-if subcommand == 'busted' then
-  require 'busted.runner'({ standalone = false })
-elseif subcommand == 'luacheck' then
-  require 'luacheck.main'
-else
-  error 'unknown subcommand'
-end

test/reporter.lua

@@ -0,0 +1,461 @@
+--- @alias test.reporter.SummaryStatus 'skipped' | 'failure' | 'error'
+
+--- @class test.reporter.ColorMap
+--- @field bright fun(s: any): string
+--- @field green fun(s: any): string
+--- @field yellow fun(s: any): string
+--- @field magenta fun(s: any): string
+--- @field red fun(s: any): string
+--- @field cyan fun(s: any): string
+--- @field dim fun(s: any): string
+
+--- @class test.reporter.FileElement
+--- @field name string
+--- @field duration? number
+
+--- @class test.reporter.Options
+--- @field verbose boolean
+--- @field summary_file string
+
+--- @class test.base_reporter
+--- @field new fun(opts: test.reporter.Options): test.base_reporter
+--- @field suite_start fun(self: test.base_reporter, repeat_index?: integer, repeat_count?: integer)
+--- @field file_start fun(self: test.base_reporter, file: test.reporter.FileElement)
+--- @field test_start fun(self: test.base_reporter, name: string)
+--- @field test_end fun(self: test.base_reporter, record: test.harness.Record)
+--- @field file_end fun(self: test.base_reporter, file: test.reporter.FileElement, test_count: integer)
+--- @field suite_end fun(self: test.base_reporter, duration: number, run_summary: test.harness.RunSummary, failure_output?: string)
+
+--- @class test.reporter : test.base_reporter
+--- @field opts test.reporter.Options
+--- @field colors test.reporter.ColorMap
+local M = {}
+M.__index = M
+
+--- @return test.reporter.ColorMap
+local function identity_colors()
+  return setmetatable({}, {
+    __index = function()
+      return function(s)
+        return s == nil and '' or tostring(s)
+      end
+    end,
+  })
+end
+
+--- @param code string
+--- @return fun(s: any): string
+local function ansi_color(code)
+  return function(s)
+    return ('\27[%sm%s\27[0m'):format(code, s == nil and '' or tostring(s))
+  end
+end
+
+local ansi_colors = {
+  bright = ansi_color('1'),
+  green = ansi_color('32'),
+  yellow = ansi_color('33'),
+  magenta = ansi_color('35'),
+  red = ansi_color('31'),
+  cyan = ansi_color('36'),
+  dim = ansi_color('2'),
+}
+
+--- @return boolean
+local function use_colors()
+  local test_colors = os.getenv('TEST_COLORS')
+  if not test_colors then
+    return true
+  end
+
+  local value = test_colors:lower()
+  return not (value == 'false' or value == '0' or value == 'no' or value == 'off')
+end
+
+--- @param path? string
+--- @return file
+local function open_summary_file(path)
+  if type(path) ~= 'string' or path == '-' then
+    return io.stdout
+  end
+
+  return (assert(io.open(path, 'w')))
+end
+
+--- @param opts test.reporter.Options
+--- @return test.reporter
+function M.new(opts)
+  local colors = identity_colors()
+  if use_colors() then
+    colors = ansi_colors
+  end
+
+  --- @type test.reporter
+  local self = setmetatable({
+    opts = opts,
+    colors = colors,
+  }, M)
+
+  return self
+end
+
+--- @param element? { duration?: number }
+--- @return number
+local function get_elapsed_time_ms(element)
+  if element and element.duration then
+    return element.duration * 1000
+  end
+
+  return tonumber('nan')
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:succ(s)
+  return self.colors.bright(self.colors.green(s))
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:skip(s)
+  return self.colors.bright(self.colors.yellow(s))
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:fail(s)
+  return self.colors.bright(self.colors.magenta(s))
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:errr(s)
+  return self.colors.bright(self.colors.red(s))
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:fpath(s)
+  return self.colors.cyan(s)
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:time(s)
+  return self.colors.dim(s)
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:sect(s)
+  return self.colors.green(self.colors.dim(s))
+end
+
+--- @private
+--- @param s any
+--- @return string
+function M:nmbr(s)
+  return self.colors.bright(s)
+end
+
+--- @private
+--- @param status test.harness.ResultStatus
+--- @return string
+function M:result_text(status)
+  if status == 'success' then
+    return ('%s\n'):format(self:succ('OK'))
+  elseif status == 'pending' then
+    return ('%s\n'):format(self:skip('SKIP'))
+  elseif status == 'failure' then
+    return ('%s\n'):format(self:fail('FAIL'))
+  end
+
+  return ('%s\n'):format(self:errr('ERR'))
+end
+
+--- @private
+--- @param status test.reporter.SummaryStatus
+--- @return string
+function M:summary_label(status)
+  if status == 'skipped' then
+    return self:skip('SKIPPED ')
+  elseif status == 'failure' then
+    return self:fail('FAILED  ')
+  end
+
+  return self:errr('ERROR   ')
+end
+
+--- @private
+--- @param status test.reporter.SummaryStatus
+--- @param count integer
+--- @return string
+function M:summary_header_noun(status, count)
+  if status == 'error' then
+    return count == 1 and 'error' or 'errors'
+  end
+
+  return count == 1 and 'test' or 'tests'
+end
+
+--- @private
+--- @param status test.reporter.SummaryStatus
+--- @param count integer
+--- @return string
+function M:summary_footer_noun(status, count)
+  if status == 'skipped' then
+    return count == 1 and 'SKIPPED TEST' or 'SKIPPED TESTS'
+  elseif status == 'failure' then
+    return count == 1 and 'FAILED TEST' or 'FAILED TESTS'
+  elseif status == 'error' then
+    return count == 1 and 'ERROR' or 'ERRORS'
+  end
+
+  return count == 1 and 'TEST' or 'TESTS'
+end
+
+--- @param message any
+--- @return string
+local function stringify_message(message)
+  if type(message) == 'string' then
+    return message
+  elseif message == nil then
+    return ''
+  end
+
+  return vim.inspect(message)
+end
+
+--- @private
+--- @param pending test.harness.Record
+--- @return boolean
+function M:na_check(pending)
+  if pending.name and vim.list_contains(vim.split(pending.name, '[ :]'), 'N/A') then
+    return true
+  end
+
+  if type(pending.message) == 'string' then
+    return vim.list_contains(vim.split(pending.message, '[ :]'), 'N/A')
+  end
+
+  return false
+end
+
+--- @private
+--- @param pending test.harness.Record
+--- @return string
+function M:pending_description(pending)
+  local message = stringify_message(pending.message)
+  if message == '' then
+    return ''
+  end
+
+  return table.concat({ message, '\n' })
+end
+
+--- @private
+--- @param failure test.harness.Record
+--- @return string
+function M:failure_description(failure)
+  local message = stringify_message(failure.message)
+  if message == '' then
+    message = 'Nil error'
+  end
+
+  local parts = { message, '\n' }
+  if self.opts.verbose and failure.traceback then
+    parts[#parts + 1] = failure.traceback
+    parts[#parts + 1] = '\n'
+  end
+
+  return table.concat(parts)
+end
+
+--- @private
+--- @param trace? test.harness.Trace
+--- @return string
+function M:get_file_line(trace)
+  if not trace or not trace.short_src then
+    return ''
+  end
+
+  local source = vim.fs.normalize(trace.short_src)
+  local line = trace.currentline or 0
+  return self:fpath(source) .. ' @ ' .. self:fpath(line) .. ': '
+end
+
+--- @private
+--- @param status test.reporter.SummaryStatus
+--- @param count integer
+--- @param list test.harness.Record[]
+--- @param describe fun(self: test.reporter, item: test.harness.Record): string
+--- @return string
+function M:get_test_list(status, count, list, describe)
+  if count == 0 then
+    return ''
+  end
+
+  local label = self:summary_label(status)
+  local parts = {
+    ('%s %s %s, listed below:\n'):format(
+      label,
+      self:nmbr(count),
+      self:summary_header_noun(status, count)
+    ),
+  }
+  local na_count = 0
+
+  for _, item in ipairs(list) do
+    if status == 'skipped' and self:na_check(item) then
+      na_count = na_count + 1
+    else
+      local fullname = self:get_file_line(item.trace) .. self:nmbr(item.name)
+      parts[#parts + 1] = ('%s %s\n'):format(label, fullname)
+      parts[#parts + 1] = describe(self, item)
+    end
+  end
+
+  if na_count > 0 then
+    parts[#parts + 1] =
+      self:nmbr(('%d N/A %s not shown\n'):format(na_count, na_count == 1 and 'test' or 'tests'))
+  end
+
+  return table.concat(parts)
+end
+
+--- @private
+--- @param status test.reporter.SummaryStatus
+--- @param count integer
+--- @return string
+function M:get_summary(status, count)
+  if count == 0 then
+    return ''
+  end
+
+  return (' %s %s\n'):format(self:nmbr(count), self:summary_footer_noun(status, count))
+end
+
+--- @private
+--- @return string
+--- @param summary test.harness.RunSummary
+function M:get_summary_string(summary)
+  local tests = summary.success_count == 1 and 'test' or 'tests'
+  local parts = {
+    ('%s %s %s.\n'):format(self:succ('PASSED  '), self:nmbr(summary.success_count), tests),
+    self:get_test_list('skipped', summary.skipped_count, summary.pendings, M.pending_description),
+    self:get_test_list('failure', summary.failure_count, summary.failures, M.failure_description),
+    self:get_test_list('error', summary.error_count, summary.errors, M.failure_description),
+  }
+
+  if (summary.skipped_count + summary.failure_count + summary.error_count) > 0 then
+    parts[#parts + 1] = '\n'
+  end
+
+  parts[#parts + 1] = self:get_summary('skipped', summary.skipped_count)
+  parts[#parts + 1] = self:get_summary('failure', summary.failure_count)
+  parts[#parts + 1] = self:get_summary('error', summary.error_count)
+  return table.concat(parts)
+end
+
+--- @return nil
+--- @param repeat_index? integer
+--- @param repeat_count? integer
+function M:suite_start(repeat_index, repeat_count)
+  if repeat_count and repeat_count > 1 and repeat_index then
+    io.write(('\nRepeating all tests (run %d of %d) . . .\n\n'):format(repeat_index, repeat_count))
+  end
+  io.write(('%s Global test environment setup.\n'):format(self:sect('--------')))
+  io.flush()
+end
+
+--- @param file test.reporter.FileElement
+function M:file_start(file)
+  io.write(
+    ('%s Running tests from %s\n'):format(
+      self:sect('--------'),
+      self:fpath(vim.fs.normalize(file.name))
+    )
+  )
+  io.flush()
+end
+
+--- @param name string
+function M:test_start(name)
+  local desc = ('%s %s'):format(_G._nvim_test_id or '', name)
+  io.write(('%s %s: '):format(self:sect('RUN     '), desc))
+  io.flush()
+end
+
+--- @private
+--- @param record { duration?: number }
+--- @param text string
+function M:write_status(record, text)
+  io.write(('%s %s'):format(self:time(('%.2f ms'):format(get_elapsed_time_ms(record))), text))
+  io.flush()
+end
+
+--- @param record test.harness.Record
+function M:test_end(record)
+  local text = self:result_text(record.status)
+  if record.status == 'failure' or record.status == 'error' then
+    text = text .. self:failure_description(record)
+  end
+
+  self:write_status(record, text)
+end
+
+--- @param file test.reporter.FileElement
+--- @param test_count integer
+function M:file_end(file, test_count)
+  io.write(
+    ('%s %s %s from %s %s\n\n'):format(
+      self:sect('--------'),
+      self:nmbr(test_count),
+      test_count == 1 and 'test' or 'tests',
+      self:fpath(vim.fs.normalize(file.name)),
+      self:time(('(%.2f ms total)'):format(get_elapsed_time_ms(file)))
+    )
+  )
+  io.flush()
+end
+
+--- @param duration number
+--- @param run_summary test.harness.RunSummary
+--- @param failure_output? string
+function M:suite_end(duration, run_summary, failure_output)
+  local tests = run_summary.test_count == 1 and 'test' or 'tests'
+  local files = run_summary.file_count == 1 and 'file' or 'files'
+
+  io.write(('%s Global test environment teardown.\n'):format(self:sect('--------')))
+  io.flush()
+
+  local summary_file = open_summary_file(self.opts.summary_file)
+  summary_file:write('\n')
+  summary_file:write(
+    ('%s %s %s from %s test %s ran. %s\n'):format(
+      self:sect('========'),
+      self:nmbr(run_summary.test_count),
+      tests,
+      self:nmbr(run_summary.file_count),
+      files,
+      self:time(('(%.2f ms total)'):format(duration * 1000))
+    )
+  )
+  summary_file:write(self:get_summary_string(run_summary))
+  if failure_output then
+    summary_file:write(failure_output)
+  end
+  summary_file:flush()
+  if summary_file ~= io.stdout then
+    summary_file:close()
+  end
+end
+
+return M

test/run_tests.zig

@@ -1,24 +1,22 @@
 const std = @import("std");
 const LazyPath = std.Build.LazyPath;
 
-pub fn testStep(b: *std.Build, kind: []const u8, nvim_bin: *std.Build.Step.Compile, lua_deps: LazyPath, config_dir: LazyPath, include_path: ?[]const LazyPath) !*std.Build.Step.Run {
+pub fn testStep(b: *std.Build, kind: []const u8, nvim_bin: *std.Build.Step.Compile, config_dir: LazyPath, include_path: ?[]const LazyPath) !*std.Build.Step.Run {
     const test_step = b.addRunArtifact(nvim_bin);
     test_step.addArg("-ll");
-    test_step.addFileArg(b.path("./test/lua_runner.lua"));
+    test_step.addFileArg(b.path("./test/runner.lua"));
-    test_step.addDirectoryArg(lua_deps);
     if (include_path) |paths| {
         for (paths) |path| {
             test_step.addPrefixedDirectoryArg("-I", path);
         }
     }
-    test_step.addArgs(&.{ "busted", "-v", "-o", "test.busted.outputHandlers.nvim", "--lazy" });
+    test_step.addArg("-v");
-    // TODO(bfredl): a bit funky with paths, should work even if we run "zig build" in a nested dir
+    test_step.addArg(b.fmt("--helper=./test/{s}/preload.lua", .{kind}));
-    test_step.addArg(b.fmt("./test/{s}/preload.lua", .{kind}));
     test_step.addArg("--lpath=./src/?.lua");
     test_step.addArg("--lpath=./runtime/lua/?.lua");
     test_step.addArg("--lpath=./?.lua");
     test_step.addPrefixedFileArg("--lpath=", config_dir.path(b, "?.lua")); // FULING: not a real file but works anyway?
-    // TODO(bfredl): look into $BUSTED_ARGS user hook, TEST_TAG,  TEST_FILTER
+    // TODO(bfredl): look into a TEST_ARGS user hook, TEST_TAG, TEST_FILTER.
     if (b.args) |args| {
         test_step.addArgs(args); // accept TEST_FILE as a positional argument
     } else {
@@ -40,12 +38,12 @@ pub fn testStep(b: *std.Build, kind: []const u8, nvim_bin: *std.Build.Step.Compi
     return test_step;
 }
 
-pub fn test_steps(b: *std.Build, nvim_bin: *std.Build.Step.Compile, depend_on: *std.Build.Step, lua_deps: LazyPath, config_dir: LazyPath, unit_paths: ?[]const LazyPath) !void {
+pub fn test_steps(b: *std.Build, nvim_bin: *std.Build.Step.Compile, depend_on: *std.Build.Step, config_dir: LazyPath, unit_paths: ?[]const LazyPath) !void {
     const empty_dir = b.addWriteFiles();
     _ = empty_dir.add(".touch", "");
     const tmpdir_create = b.addInstallDirectory(.{ .source_dir = empty_dir.getDirectory(), .install_dir = .prefix, .install_subdir = "Xtest_tmpdir/" });
 
-    const functional_tests = try testStep(b, "functional", nvim_bin, lua_deps, config_dir, null);
+    const functional_tests = try testStep(b, "functional", nvim_bin, config_dir, null);
     functional_tests.step.dependOn(depend_on);
     functional_tests.step.dependOn(&tmpdir_create.step);
 
@@ -53,7 +51,7 @@ pub fn test_steps(b: *std.Build, nvim_bin: *std.Build.Step.Compile, depend_on: *
     functionaltest_step.dependOn(&functional_tests.step);
 
     if (unit_paths) |paths| {
-        const unit_tests = try testStep(b, "unit", nvim_bin, lua_deps, config_dir, paths);
+        const unit_tests = try testStep(b, "unit", nvim_bin, config_dir, paths);
         unit_tests.step.dependOn(depend_on);
         unit_tests.step.dependOn(&tmpdir_create.step);
 

test/runner.lua

@@ -0,0 +1,35 @@
+local uv = vim.uv
+
+---@return string
+local function repo_root()
+  local source = debug.getinfo(1, 'S').source
+  assert(type(source) == 'string' and vim.startswith(source, '@'), 'failed to resolve runner path')
+  local script_path = assert(uv.fs_realpath(source:sub(2)), 'failed to resolve runner path')
+  return vim.fs.dirname(vim.fs.dirname(script_path))
+end
+
+---@param roots string[]
+local function prepend_package_roots(roots)
+  local entries = {}
+  for _, root in ipairs(roots) do
+    entries[#entries + 1] = root .. '/?.lua'
+    entries[#entries + 1] = root .. '/?/init.lua'
+  end
+
+  package.path = table.concat(entries, ';') .. ';' .. package.path
+end
+
+_G.c_include_path = {}
+while _G.arg[1] and vim.startswith(_G.arg[1], '-I') do
+  table.insert(_G.c_include_path, string.sub(table.remove(_G.arg, 1), 3))
+end
+
+local root = repo_root()
+prepend_package_roots({ root, root .. '/test', '.', './test' })
+
+local exit_code = require('test.harness').main(_G.arg)
+io.stdout:flush()
+io.stderr:flush()
+
+-- Close the standalone Lua state before exit so sanitizers see Lua-owned cleanup.
+os.exit(exit_code, true)

test/testutil.lua

@@ -1,10 +1,9 @@
-local luaassert = require('luassert')
+local test_assert = require('test.assert')
-local busted = require('busted')
+---@type test.harness
+local harness = require('test.harness')
 local uv = vim.uv
 local Paths = require('test.cmakeconfig.paths')
 
-luaassert:set_parameter('TableFormatLevel', 100)
-
 --- Functions executing in the context of the test runner (not the current nvim test session).
 --- @class test.testutil
 local M = {
@@ -86,7 +85,7 @@ function M.retry(max, max_ms, fn)
     end
     uv.update_time() -- Update cached value of luv.now() (libuv: uv_now()).
     if (max and tries >= max) or (uv.now() - start_time > timeout) then
-      busted.fail(string.format('retry() attempts: %d\n%s', tries, tostring(result)), 2)
+      error(string.format('retry() attempts: %d\n%s', tries, tostring(result)), 2)
     end
     tries = tries + 1
     uv.sleep(20) -- Avoid hot loop...
@@ -100,10 +99,10 @@ local check_logs_useless_lines = {
 }
 
 function M.eq(expected, actual, context)
-  return luaassert.are.same(expected, actual, context)
+  return test_assert.eq(expected, actual, context)
 end
 function M.neq(expected, actual, context)
-  return luaassert.are_not.same(expected, actual, context)
+  return test_assert.neq(expected, actual, context)
 end
 
 --- Compare paths after resolving symlinks with realpath.
@@ -125,15 +124,6 @@ function M.ok(cond, expected, actual)
   return assert(cond, msg)
 end
 
-local function epicfail(state, arguments, _)
-  state.failure_message = arguments[1]
-  return false
-end
-luaassert:register('assertion', 'epicfail', epicfail)
-function M.fail(msg)
-  return luaassert.epicfail(msg)
-end
-
 --- @param pat string
 --- @param actual string
 --- @return boolean
@@ -365,7 +355,7 @@ function M.check_logs()
       end
     end
   end
-  luaassert(
+  test_assert(
     0 == #runtime_errors,
     string.format('Found runtime errors in logfile(s): %s', table.concat(runtime_errors, ', '))
   )
@@ -789,34 +779,15 @@ end
 --- @param name? 'cirrus'|'github'
 --- @return boolean
 function M.is_ci(name)
-  local any = (name == nil)
+  return harness.is_ci(name)
-  assert(any or name == 'github' or name == 'cirrus')
-  local gh = ((any or name == 'github') and nil ~= os.getenv('GITHUB_ACTIONS'))
-  local cirrus = ((any or name == 'cirrus') and nil ~= os.getenv('CIRRUS_CI'))
-  return gh or cirrus
 end
 
 -- Gets the (tail) contents of `logfile`.
 -- Also moves the file to "${NVIM_LOG_FILE}.displayed" on CI environments.
 function M.read_nvim_log(logfile, ci_rename)
   logfile = logfile or os.getenv('NVIM_LOG_FILE') or 'nvim.log'
-  assert(uv.fs_stat(logfile), ('logfile not found: %q'):format(logfile))
+  local log = harness.read_nvim_log(logfile, ci_rename)
-  local is_ci = M.is_ci()
+  assert(log, ('logfile not found: %q'):format(logfile))
-  local keep = is_ci and 100 or 10
-  local lines = M.read_file_list(logfile, -keep) or {}
-  local log = (
-    ('-'):rep(78)
-    .. '\n'
-    .. string.format('$NVIM_LOG_FILE: %s\n', logfile)
-    .. (#lines > 0 and '(last ' .. tostring(keep) .. ' lines)\n' or '(empty)\n')
-  )
-  for _, line in ipairs(lines) do
-    log = log .. line .. '\n'
-  end
-  log = log .. ('-'):rep(78) .. '\n'
-  if is_ci and ci_rename then
-    os.rename(logfile, logfile .. '.displayed')
-  end
   return log
 end
 
@@ -843,7 +814,7 @@ function M.expect_events(expected, received, kind)
     for _, e in ipairs(expected) do
       msg = msg .. '  ' .. vim.inspect(e) .. ';\n'
     end
-    M.fail(msg)
+    error(msg, 2)
   end
   return received
 end

test/unit/os/fs_spec.lua

@@ -76,8 +76,8 @@ describe('fs.c', function()
     uv.fs_symlink('test.file', 'unit-test-directory/test_link.file')
 
     uv.fs_symlink('non_existing_file.file', 'unit-test-directory/test_broken_link.file')
-    -- The tests are invoked with an absolute path to `busted` executable.
+    -- The tests are invoked with an absolute executable path in arg[0].
-    absolute_executable = arg[0]
+    absolute_executable = vim.fs.normalize(assert(uv.exepath()))
     -- Split the absolute_executable path into a directory and filename.
     directory, executable_name = string.match(absolute_executable, '^(.*)/(.*)$')
   end)

test/unit/path_spec.lua

@@ -397,14 +397,6 @@ describe('path.c', function()
   setup(function()
     mkdir('unit-test-directory')
     io.open('unit-test-directory/test.file', 'w'):close()
-
-    -- Since the tests are executed, they are called by an executable. We use
-    -- that executable for several asserts.
-    local absolute_executable = arg[0]
-
-    -- Split absolute_executable into a directory and the actual file name for
-    -- later usage.
-    local directory, executable_name = string.match(absolute_executable, '^(.*)/(.*)$') -- luacheck: ignore
   end)
 
   teardown(function()

test/unit/preload.lua

@@ -1,6 +1,6 @@
--- Modules loaded here will not be cleared and reloaded by Busted.
+-- Modules loaded here will not be cleared and reloaded by the local harness.
--- Busted started doing this to help provide more isolation.  See issue #62
+-- Keeping these preloaded preserves cross-file setup while still resetting
--- for more information about this.
+-- non-helper modules between files.
 require('ffi')
 require('test.unit.testutil')
 require('test.unit.preprocess')

test/unit/tempfile_spec.lua

@@ -46,7 +46,7 @@ describe('tempfile related functions', function()
 
     itp('generate name of non-existing file', function()
       local file = vim_tempname()
-      assert.truthy(file)
+      assert(file)
       assert.False(lib.os_path_exists(file))
     end)
 

test/unit/testtest_spec.lua

@@ -1,5 +1,4 @@
 local t = require('test.unit.testutil')
-local assert = require('luassert')
 
 local itp = t.gen_itp(it)
 
@@ -11,7 +10,7 @@ if os.getenv('NVIM_TEST_RUN_TESTTEST') ~= '1' then
 end
 describe('test code', function()
   itp('does not hang when working with lengthy errors', function()
-    assert.just_fail(('x'):rep(65536))
+    error(('x'):rep(65536), 0)
   end)
   itp('shows trace after exiting abnormally', function()
     sc.exit(0)

test/unit/testutil.lua

@@ -4,8 +4,7 @@ local Set = require('test.unit.set')
 local Preprocess = require('test.unit.preprocess')
 local t_global = require('test.testutil')
 local paths = t_global.paths
-local assert = require('luassert')
+local assert = require('test.assert')
-local say = require('say')
 
 local check_cores = t_global.check_cores
 local dedent = t_global.dedent
@@ -538,19 +537,6 @@ if os.getenv('NVIM_TEST_PRINT_SYSCALLS') == '1' then
   end
 end
 
-local function just_fail(_)
-  return false
-end
-say:set('assertion.just_fail.positive', '%s')
-say:set('assertion.just_fail.negative', '%s')
-assert:register(
-  'assertion',
-  'just_fail',
-  just_fail,
-  'assertion.just_fail.positive',
-  'assertion.just_fail.negative'
-)
-
 local hook_fnamelen = 30
 local hook_sfnamelen = 30
 local hook_numlen = 5
@@ -769,7 +755,7 @@ local function check_child_err(rd)
       end
     end
     if err ~= '' then
-      assert.just_fail(err)
+      error(err, 0)
     end
   end
 end
@@ -810,7 +796,7 @@ local function gen_itp(it)
     end
 
     -- Pre-emptively calculating error location, wasteful, ugh!
-    -- But the way this code messes around with busted implies the real location is strictly
+    -- But the way this code wraps the local harness means the real location is strictly
     -- not available in the parent when an actual error occurs. so we have to do this here.
     local location = debug.traceback()
     it(name, function()

test/unit/vterm_spec.lua

@@ -275,6 +275,13 @@ local function push(input, vt)
   vterm.vterm_input_write(vt, input, string.len(input))
 end
 
+-- vterm_input_write() can synchronously invoke the Lua callbacks installed
+-- above. LuaJIT must not JIT-compile an FFI call that re-enters Lua, or the
+-- test can panic with "bad callback".
+if jit then
+  jit.off(push, true)
+end
+
 local function expect(expected)
   local actual = read_rm()
   t.eq(expected .. '\n', actual)