Added cool output to failed tests

generator/test-common.go

@@ -42,12 +42,42 @@ func testReader (test *testing.T, correct string, inputs ...io.Reader) {
 		test.Error("generator returned error:", err)
 		return
 	}
+
+	printColumns := func (left, right string) {
+		test.Logf("%-80v | %v", left, right)
+	}
+
+	printColumnsStyle := func (left, right string, style string) {
+		test.Logf("\033[%s%-80v - %v\033[0m", style, left, right)
+	}
 	
 	got := output.String()
 	if got != correct {
 		test.Logf("results do not match")
-		test.Logf("got:\n%v", got)
-		test.Logf("correct:\n%v", correct)
+
+		got     = strings.ReplaceAll(got,     "\t", "        ")
+		correct = strings.ReplaceAll(correct, "\t", "        ")
+		
+		got     := strings.Split(got,     "\n")
+		correct := strings.Split(correct, "\n")
+		length  := len(got)
+		if len(correct) > len(got) { length = len(correct) }
+
+		printColumns("CORRECT:", "GOT:")
+		test.Log()
+		for index := 0; index < length; index ++ {
+			left  := ""
+			right := ""
+			if index < len(got)     { left  = got[index]     }
+			if index < len(correct) { right = correct[index] }
+
+			if left != right {
+				printColumnsStyle(left, right, "31m")
+			} else {
+				printColumns(left, right)
+			}
+			
+		}
 		test.Fail()
 	}
 }