Fix the testrunner.ErrUnexpectedOutput.Error() method

Author: thewizardplusplus

test-runner/errors.go

@@ -30,7 +30,8 @@ type ErrUnexpectedOutput struct {
 // Error ...
 func (err ErrUnexpectedOutput) Error() string {
 	return fmt.Sprintf(
-		"unexpected output: expected - %q, actual - %q",
+		"unexpected output (input - %q): expected - %q, actual - %q",
+		err.Input,
 		err.ExpectedOutput,
 		err.ActualOutput,
 	)

test-runner/errors_test.go

@@ -22,7 +22,7 @@ func TestErrUnexpectedOutput_Error(test *testing.T) {
 		ActualOutput: "actual output",
 	}
 
-	const wantedErrMessage = "unexpected output: " +
+	const wantedErrMessage = `unexpected output (input - "input"): ` +
 		`expected - "expected output", actual - "actual output"`
 	assert.EqualError(test, err, wantedErrMessage)
 }