Merge #178

178: minor refactor of unittest implementation r=saem a=krux02

generally speaking unittesting is very important, but the unittest
modules causes nothing but problems. The problem is, unittest pretty
much uses all problematic metaprogramming APIs at the same time. This
should be changed, step by step.

 * `template print(a,b: untyped)` -> `proc print[T](name: string, value: T)`
 * `newIdentNode(":c" & $counter)` -> `genSym`
 * `template assign` -> `newVarStmt`



Co-authored-by: Arne Döring <a.doering@digiblue.de>

lib/pure/unittest.nim

@@ -632,6 +632,13 @@ template skip* =
   testStatusIMPL = TestStatus.SKIPPED
   checkpoints = @[]
 
+proc print[T: not typedesc](name: string, value: T) =
+  when compiles(string($value)):
+    checkpoint(name & " was " & $value)
+
+proc print[T](name: string, typ: typedesc[T]) =
+  checkpoint(name & " was " & $typ)
+
 macro check*(conditions: untyped): untyped =
   ## Verify if a statement or a list of statements is true.
   ## A helpful error message and set checkpoints are printed out on
@@ -649,47 +656,36 @@ macro check*(conditions: untyped): untyped =
 
   let checked = callsite()[1]
 
-  template asgn(a: untyped, value: typed) =
-    var a = value # XXX: we need "var: var" here in order to
-                  # preserve the semantics of var params
-
-  template print(name: untyped, value: typed) =
-    when compiles(string($value)):
-      checkpoint(name & " was " & $value)
-
   proc inspectArgs(exp: NimNode): tuple[assigns, check, printOuts: NimNode] =
     result.check = copyNimTree(exp)
     result.assigns = newNimNode(nnkStmtList)
     result.printOuts = newNimNode(nnkStmtList)
 
-    var counter = 0
-
     if exp[0].kind in {nnkIdent, nnkOpenSymChoice, nnkClosedSymChoice, nnkSym} and
         $exp[0] in ["not", "in", "notin", "==", "<=",
                     ">=", "<", ">", "!=", "is", "isnot"]:
 
       for i in 1 ..< exp.len:
         if exp[i].kind notin nnkLiterals:
-          inc counter
           let argStr = exp[i].toStrLit
           let paramAst = exp[i]
           if exp[i].kind == nnkIdent:
-            result.printOuts.add getAst(print(argStr, paramAst))
+            result.printOuts.add newCall(bindSym"print", argStr, paramAst)
           if exp[i].kind in nnkCallKinds + {nnkDotExpr, nnkBracketExpr, nnkPar} and
                   (exp[i].typeKind notin {ntyTypeDesc} or $exp[0] notin ["is", "isnot"]):
-            let callVar = newIdentNode(":c" & $counter)
-            result.assigns.add getAst(asgn(callVar, paramAst))
+            let callVar = genSym(nskVar, "c")
+            result.assigns.add newVarStmt(callVar, paramAst)
             result.check[i] = callVar
-            result.printOuts.add getAst(print(argStr, callVar))
+            result.printOuts.add newCall(bindSym"print", argStr, callVar)
           if exp[i].kind == nnkExprEqExpr:
             # ExprEqExpr
             #   Ident "v"
             #   IntLit 2
             result.check[i] = exp[i][1]
           if exp[i].typeKind notin {ntyTypeDesc}:
-            let arg = newIdentNode(":p" & $counter)
-            result.assigns.add getAst(asgn(arg, paramAst))
-            result.printOuts.add getAst(print(argStr, arg))
+            let arg = genSym(nskVar, "p")
+            result.assigns.add newVarStmt(arg, paramAst)
+            result.printOuts.add newCall(bindSym"print", argStr, arg)
             if exp[i].kind != nnkExprEqExpr:
               result.check[i] = arg
             else: