improve marking mismatches a bit in test cases

Author: ktoso

Tests/JExtractSwiftTests/Asserts/TextAssertions.swift

@@ -179,7 +179,9 @@ func assertOutput(
         print("==== ---------------------------------------------------------------")
         print("Expected output:")
         for (n, e) in expectedLines.enumerated() {
-          print("\(n): \(e)".yellow(if: diffLineNumbers.map({$0 - matchingOutputOffset}).contains(n)))
+          let isMismatch = diffLineNumbers.map({$0 - matchingOutputOffset}).contains(n)
+          let marker = isMismatch ? " // <<<<<<<<<<< mismatch" : ""
+          print("\(n): \(e)\(marker)".yellow(if: isMismatch))
         }
       }
 
@@ -188,8 +190,7 @@ func assertOutput(
       let printFromLineNo = matchingOutputOffset
       for (n, g) in gotLines.enumerated() where n >= printFromLineNo {
         let baseLine = "\(n): \(g)"
-        var line = baseLine
-        print(line)
+        print(baseLine)
       }
       print("==== ---------------------------------------------------------------\n")
     }
@@ -241,14 +242,18 @@ func assertOutput(
       print("==== ---------------------------------------------------------------")
       print("Expected output:")
       for (n, e) in expectedLines.enumerated() {
-        print("\(e)".yellow(if: diffLineNumbers.contains(n)))
+        let isMismatch = diffLineNumbers.contains(n)
+        let marker = isMismatch ? " // <<<<<<<< error: mismatch" : ""
+        print("\(e)\(marker)".yellow(if: isMismatch))
       }
     }
 
     print("==== ---------------------------------------------------------------")
     print("Got output:")
     for (n, g) in gotLines.enumerated() {
-      print("\(g)".red(if: diffLineNumbers.contains(n)))
+      let isMismatch = diffLineNumbers.contains(n)
+      let marker = isMismatch ? "// <<<<<<<< error: mismatch" : ""
+      print("\(g)\(marker)".red(if: isMismatch))
     }
     print("==== ---------------------------------------------------------------\n")
   }