make megatest consistent with unjoined tests wrt newlines, honor newlines in output spec (#16151)

* fix megatest newlines
* still allow missing trailing newline for now but in a more strict way than before

testament/categories.nim

@@ -591,12 +591,14 @@ proc isJoinableSpec(spec: TSpec): bool =
     if spec.file.readFile.contains "when isMainModule":
       result = false
 
-proc norm(s: var string) =
-  while true:
-    let tmp = s.replace("\n\n", "\n")
-    if tmp == s: break
-    s = tmp
-  s = s.strip
+when false:
+  proc norm(s: var string) =
+    ## strip empty newlines
+    while true:
+      let tmp = s.replace("\n\n", "\n")
+      if tmp == s: break
+      s = tmp
+    s = s.strip
 
 proc quoted(a: string): string =
   # todo: consider moving to system.nim
@@ -654,16 +656,16 @@ proc runJoinedTest(r: var TResults, cat: Category, testsDir: string) =
     echo buf.string
     quit(failString & "megatest execution failed")
 
-  norm buf.string
   const outputExceptedFile = "outputExpected.txt"
   const outputGottenFile = "outputGotten.txt"
   writeFile(outputGottenFile, buf.string)
   var outputExpected = ""
   for i, runSpec in specs:
     outputExpected.add marker & runSpec.file & "\n"
-    outputExpected.add runSpec.output.strip
-    outputExpected.add '\n'
-  norm outputExpected
+    if runSpec.output.len > 0:
+      outputExpected.add runSpec.output
+      if not runSpec.output.endsWith "\n":
+        outputExpected.add '\n'
 
   if buf.string != outputExpected:
     writeFile(outputExceptedFile, outputExpected)

testament/specs.nim

@@ -280,7 +280,7 @@ proc parseSpec*(filename: string): TSpec =
       of "output":
         if result.outputCheck != ocSubstr:
           result.outputCheck = ocEqual
-        result.output = strip(e.value)
+        result.output = e.value
       of "input":
         result.input = e.value
       of "outputsub":

testament/testament.nim

@@ -469,6 +469,10 @@ proc checkDisabled(r: var TResults, test: TTest): bool =
 
 var count = 0
 
+proc equalModuloLastNewline(a, b: string): bool =
+  # allow lazy output spec that omits last newline, but really those should be fixed instead
+  result = a == b or b.endsWith("\n") and a == b[0 ..< ^1]
+
 proc testSpecHelper(r: var TResults, test: var TTest, expected: TSpec,
                     target: TTarget, nimcache: string, extraOptions = "") =
   test.startTime = epochTime()
@@ -513,16 +517,18 @@ proc testSpecHelper(r: var TResults, test: var TTest, expected: TSpec,
           if exitCode != 0: exitCode = 1
           let bufB =
             if expected.sortoutput:
-              var x = splitLines(strip(buf.string))
+              var buf2 = buf.string
+              buf2.stripLineEnd
+              var x = splitLines(buf2)
               sort(x, system.cmp)
-              join(x, "\n")
+              join(x, "\n") & "\n"
             else:
-              strip(buf.string)
+              buf.string
           if exitCode != expected.exitCode:
             r.addResult(test, target, "exitcode: " & $expected.exitCode,
                               "exitcode: " & $exitCode & "\n\nOutput:\n" &
                               bufB, reExitcodesDiffer)
-          elif (expected.outputCheck == ocEqual and expected.output != bufB) or
+          elif (expected.outputCheck == ocEqual and not expected.output.equalModuloLastNewline(bufB)) or
               (expected.outputCheck == ocSubstr and expected.output notin bufB):
             given.err = reOutputsDiffer
             r.addResult(test, target, expected.output, bufB, reOutputsDiffer)