improve nimsuggest/tester, minor improvements to koch.nim (#17879)

* improve nimsuggest/tester

* koch improvements

nimsuggest/tester.nim

@@ -2,6 +2,8 @@
 # Every test file can have a #[!]# comment that is deleted from the input
 # before 'nimsuggest' is invoked to ensure this token doesn't make a
 # crucial difference for Nim's parser.
+# When debugging, to run a single test, use for e.g.:
+# `nim r nimsuggest/tester.nim nimsuggest/tests/tsug_accquote.nim`
 
 import os, osproc, strutils, streams, re, sexp, net
 
@@ -13,16 +15,16 @@ type
     disabled: bool
 
 const
-  curDir = when defined(windows): "" else: ""
   DummyEof = "!EOF!"
-
-template tpath(): untyped = getAppDir() / "tests"
+  tpath = "nimsuggest/tests"
+  # we could also use `stdtest/specialpaths`
 
 import std/compilesettings
 
 proc parseTest(filename: string; epcMode=false): Test =
   const cursorMarker = "#[!]#"
-  let nimsug = curDir & addFileExt("nimsuggest", ExeExt)
+  let nimsug = "bin" / addFileExt("nimsuggest", ExeExt)
+  doAssert nimsug.fileExists, nimsug
   const libpath = querySetting(libPath)
   result.filename = filename
   result.dest = getTempDir() / extractFilename(filename)
@@ -63,7 +65,7 @@ proc parseTest(filename: string; epcMode=false): Test =
       elif x.startsWith(">"):
         # since 'markers' here are not complete yet, we do the $substitutions
         # afterwards
-        result.script.add((x.substr(1).replaceWord("$path", tpath()), ""))
+        result.script.add((x.substr(1).replaceWord("$path", tpath), ""))
       elif x.len > 0:
         # expected output line:
         let x = x % ["file", filename, "lib", libpath]
@@ -104,7 +106,7 @@ proc parseCmd(c: string): seq[string] =
 proc edit(tmpfile: string; x: seq[string]) =
   if x.len != 3 and x.len != 4:
     quit "!edit takes two or three arguments"
-  let f = if x.len >= 4: tpath() / x[3] else: tmpfile
+  let f = if x.len >= 4: tpath / x[3] else: tmpfile
   try:
     let content = readFile(f)
     let newcontent = content.replace(x[1], x[2])
@@ -121,12 +123,12 @@ proc exec(x: seq[string]) =
 
 proc copy(x: seq[string]) =
   if x.len != 3: quit "!copy takes two arguments"
-  let rel = tpath()
+  let rel = tpath
   copyFile(rel / x[1], rel / x[2])
 
 proc del(x: seq[string]) =
   if x.len != 2: quit "!del takes one argument"
-  removeFile(tpath() / x[1])
+  removeFile(tpath / x[1])
 
 proc runCmd(cmd, dest: string): bool =
   result = cmd[0] == '!'
@@ -317,7 +319,7 @@ proc runTest(filename: string): int =
     try:
       inp.writeLine("quit")
       inp.flush()
-    except:
+    except IOError, OSError:
       # assume it's SIGPIPE, ie, the child already died
       discard
     close(p)
@@ -334,7 +336,7 @@ proc main() =
     failures += runTest(xx)
     failures += runEpcTest(xx)
   else:
-    for x in walkFiles(tpath() / "t*.nim"):
+    for x in walkFiles(tpath / "t*.nim"):
       echo "Test ", x
       let xx = expandFilename x
       when not defined(windows):