tree-sitter: add basic testing on ci

build tree-sitter c parser on ci for testing purposes

test/functional/lua/tree_sitter_spec.lua

@@ -0,0 +1,67 @@
+-- Test suite for testing interactions with API bindings
+local helpers = require('test.functional.helpers')(after_each)
+
+local meths = helpers.meths
+local clear = helpers.clear
+local eq = helpers.eq
+local insert = helpers.insert
+local meth_pcall = helpers.meth_pcall
+local exec_lua = helpers.exec_lua
+local iswin = helpers.iswin
+
+before_each(clear)
+
+describe('tree-sitter API', function()
+  -- error tests not requiring a parser library
+  it('handles basic errors', function()
+    --eq({false, 'Error executing lua: vim.schedule: expected function'},
+    --   meth_pcall(meths.execute_lua, "parser = vim.tree_sitter.create_parser(0, 'nosuchlang')", {}))
+
+
+
+  end)
+
+  local ts_path = os.getenv("TREE_SITTER_DIR")
+
+  describe('with C parser', function()
+    if ts_path == nil then
+      it("works", function() pending("TREE_SITTER_PATH not set, skipping tree-sitter parser tests") end)
+      return
+    end
+
+    before_each(function()
+      -- TODO the .so/.dylib/.dll thingie
+      local path = ts_path .. '/bin/c'..(iswin() and '.dll' or '.so')
+      exec_lua([[
+        local path = ...
+        vim.tree_sitter.add_language(path,'c')
+
+      ]], path)
+    end)
+
+    it('parses buffer', function()
+      insert([[
+        int main() {
+          int x = 3;
+        }]])
+
+      exec_lua([[
+        parser = vim.tree_sitter.create_parser(0, "c")
+        tree = parser:parse_tree()
+        root = tree:root()
+      ]])
+
+      --eq("<parser>", exec_lua("return tostring(parser)"))
+      eq("<tree>", exec_lua("return tostring(tree)"))
+      eq("<node translation_unit>", exec_lua("return tostring(root)"))
+      eq({0,0,3,0}, exec_lua("return {root:range()}"))
+
+      eq(1, exec_lua("return root:child_count()"))
+      exec_lua("child = root:child(0)")
+      eq("<node function_definition>", exec_lua("return tostring(child)"))
+      eq({0,0,2,1}, exec_lua("return {child:range()}"))
+    end)
+
+  end)
+end)
+