testament: generic N-fold batching: windows CI 37mn=>16m (#14823)

* testament: run CI faster thanks to batching
* move ta_in, tstdin into existing tosproc
* move ta_out,tafalse,texitcode,tstderr into existing tosproc
* joinable osproc
* move tstdout into existing tosproc
* spec: batchable; fix tests
* fixup

tests/stdlib/tosproc.nim

@@ -5,9 +5,10 @@ joinable: false
 #[
 joinable: false
 because it'd need cleanup up stdout
-]#
 
-import stdtest/[specialpaths, unittest_light]
+see also: tests/osproc/*.nim; consider merging those into a single test here
+(easier to factor and test more things as a single self contained test)
+]#
 
 when defined(case_testfile): # compiled test file for child process
   from posix import exitnow
@@ -51,22 +52,58 @@ when defined(case_testfile): # compiled test file for child process
       echo args[1]
   main()
 
-else:
+elif defined(case_testfile2):
+  import strutils
+  let x = stdin.readLine()
+  echo x.parseInt + 5
 
+elif defined(case_testfile3):
+  echo "start ta_out"
+  stdout.writeLine("to stdout")
+  stdout.flushFile()
+  stdout.writeLine("to stdout")
+  stdout.flushFile()
+
+  stderr.writeLine("to stderr")
+  stderr.flushFile()
+  stderr.writeLine("to stderr")
+  stderr.flushFile()
+
+  stdout.writeLine("to stdout")
+  stdout.flushFile()
+  stdout.writeLine("to stdout")
+  stdout.flushFile()
+  echo "end ta_out"
+
+elif defined(case_testfile4):
+  import system # we could remove that
+  quit(QuitFailure)
+
+else: # main driver
+  import stdtest/[specialpaths, unittest_light]
   import os, osproc, strutils
   const nim = getCurrentCompilerExe()
+  const sourcePath = currentSourcePath()
+  let dir = getCurrentDir() / "tests" / "osproc"
+
+  template deferScoped(cleanup, body) =
+    # pending https://github.com/nim-lang/RFCs/issues/236#issuecomment-646855314
+    # xxx move to std/sugar or (preferably) some low level module
+    try: body
+    finally: cleanup
+
+  # we're testing `execShellCmd` so don't rely on it to compile test file
+  # note: this should be exported in posix.nim
+  proc c_system(cmd: cstring): cint {.importc: "system", header: "<stdlib.h>".}
+
+  proc compileNimProg(opt: string, name: string): string =
+    result = buildDir / name.addFileExt(ExeExt)
+    let cmd = "$# c -o:$# --hints:off $# $#" % [nim.quoteShell, result.quoteShell, opt, sourcePath.quoteShell]
+    doAssert c_system(cmd) == 0, $cmd
+    doAssert result.fileExists
 
   block execShellCmdTest:
-    ## first, compile child program
-    const sourcePath = currentSourcePath()
-    let output = buildDir / "D20190111T024543".addFileExt(ExeExt)
-    let cmd = "$# c -o:$# -d:release -d:case_testfile $#" % [nim, output,
-        sourcePath]
-    # we're testing `execShellCmd` so don't rely on it to compile test file
-    # note: this should be exported in posix.nim
-    proc c_system(cmd: cstring): cint {.importc: "system",
-      header: "<stdlib.h>".}
-    assertEquals c_system(cmd), 0
+    let output = compileNimProg("-d:release -d:case_testfile", "D20190111T024543")
 
     ## use it
     template runTest(arg: string, expected: int) =
@@ -79,7 +116,7 @@ else:
     runTest("quit_139", 139)
 
   block execProcessTest:
-    let dir = parentDir(currentSourcePath())
+    let dir = sourcePath.parentDir
     let (_, err) = execCmdEx(nim & " c " & quoteShell(dir / "osproctest.nim"))
     doAssert err == 0
     let exePath = dir / addFileExt("osproctest", ExeExt)
@@ -101,6 +138,7 @@ else:
       discard
 
   import std/streams
+
   block: # test for startProcess (more tests needed)
     # bugfix: windows stdin.close was a noop and led to blocking reads
     proc startProcessTest(command: string, options: set[ProcessOption] = {
@@ -126,6 +164,56 @@ else:
     var result = startProcessTest("nim r --hints:off -", options = {}, input = "echo 3*4")
     doAssert result == ("12\n", 0)
 
+  block: # startProcess stdin (replaces old test `tstdin` + `ta_in`)
+    let output = compileNimProg("-d:case_testfile2", "D20200626T215919")
+    var p = startProcess(output, dir) # dir not needed though
+    p.inputStream.write("5\n")
+    p.inputStream.flush()
+    var line = ""
+    var s: seq[string]
+    while p.outputStream.readLine(line.TaintedString):
+      s.add line
+    doAssert s == @["10"]
+
+  block:
+    let output = compileNimProg("-d:case_testfile3", "D20200626T221233")
+    var x = newStringOfCap(120)
+    block: # startProcess stdout poStdErrToStdOut (replaces old test `tstdout` + `ta_out`)
+      var p = startProcess(output, dir, options={poStdErrToStdOut})
+      deferScoped: p.close()
+      do:
+        var sout: seq[string]
+        while p.outputStream.readLine(x.TaintedString): sout.add x
+        doAssert sout == @["start ta_out", "to stdout", "to stdout", "to stderr", "to stderr", "to stdout", "to stdout", "end ta_out"]
+    block: # startProcess stderr (replaces old test `tstderr` + `ta_out`)
+      var p = startProcess(output, dir, options={})
+      deferScoped: p.close()
+      do:
+        var serr, sout: seq[string]
+        while p.errorStream.readLine(x.TaintedString): serr.add x
+        while p.outputStream.readLine(x.TaintedString): sout.add x
+        doAssert serr == @["to stderr", "to stderr"]
+        doAssert sout == @["start ta_out", "to stdout", "to stdout", "to stdout", "to stdout", "end ta_out"]
+
+  block: # startProcess exit code (replaces old test `texitcode` + `tafalse`)
+    let output = compileNimProg("-d:case_testfile4", "D20200626T224758")
+    var p = startProcess(output, dir)
+    doAssert waitForExit(p) == QuitFailure
+    p = startProcess(output, dir)
+    var running = true
+    while running:
+      # xxx: avoid busyloop?
+      running = running(p)
+    doAssert waitForExit(p) == QuitFailure
+
+    # make sure that first call to running() after process exit returns false
+    p = startProcess(output, dir)
+    for j in 0..<30: # refs #13449
+      os.sleep(50)
+      if not running(p): break
+    doAssert not running(p)
+    doAssert waitForExit(p) == QuitFailure # avoid zombies
+
   import std/strtabs
   block execProcessTest:
     var result = execCmdEx("nim r --hints:off -", options = {}, input = "echo 3*4")