a bit linting and some tests are online again

Former-commit-id: bd5463a169a36b078dba1c1b6e7dd3ffbd627617

core/errors/errors.go

@@ -11,7 +11,6 @@ import (
 
 var (
 	// Prefix the error prefix, applies to each error's message.
-	// Should not be changed.
 	Prefix = ""
 	// NewLine adds a new line to the end of each error's message
 	// defaults to true

core/errors/errors_test.go

@@ -0,0 +1,98 @@
+// black-box testing
+package errors_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/kataras/iris/core/errors"
+)
+
+var errMessage = "User with mail: %s already exists"
+var errUserAlreadyExists = errors.New(errMessage)
+var userMail = "user1@mail.go"
+var expectedUserAlreadyExists = "User with mail: user1@mail.go already exists"
+
+func getNewLine() string {
+	if errors.NewLine {
+		return "\n"
+	}
+	return ""
+}
+
+func ExampleError() {
+	fmt.Print(errUserAlreadyExists.Format(userMail))
+	// first output first Output line
+	fmt.Print(errUserAlreadyExists.Format(userMail).Append("Please change your mail addr"))
+	// second output second and third Output lines
+
+	// Output:
+	// User with mail: user1@mail.go already exists
+	// User with mail: user1@mail.go already exists
+	// Please change your mail addr
+}
+
+func do(method string, testErr *errors.Error, expectingMsg string, t *testing.T) {
+	formattedErr := func() error {
+		return testErr.Format(userMail)
+	}()
+
+	if formattedErr.Error() != expectingMsg {
+		t.Fatalf("error %s failed, expected:\n%s got:\n%s", method, expectingMsg, formattedErr.Error())
+	}
+}
+
+func TestFormat(t *testing.T) {
+	expected := errors.Prefix + expectedUserAlreadyExists + getNewLine()
+	do("Format Test", errUserAlreadyExists, expected, t)
+}
+
+func TestAppendErr(t *testing.T) {
+	errors.NewLine = true
+	errors.Prefix = "error: "
+
+	errChangeMailMsg := "Please change your mail addr"
+	errChangeMail := fmt.Errorf(errChangeMailMsg)                                                           // test go standard error
+	expectedErrorMessage := errUserAlreadyExists.Format(userMail).Error() + errChangeMailMsg + getNewLine() // first Prefix and last newline lives inside do
+	errAppended := errUserAlreadyExists.AppendErr(errChangeMail)
+	do("Append Test Standard error type", &errAppended, expectedErrorMessage, t)
+}
+
+func TestAppendError(t *testing.T) {
+	errors.NewLine = true
+	errors.Prefix = "error: "
+
+	errChangeMailMsg := "Please change your mail addr"
+	errChangeMail := errors.New(errChangeMailMsg)                                                                // test Error struct
+	expectedErrorMessage := errUserAlreadyExists.Format(userMail).Error() + errChangeMail.Error() + getNewLine() // first Prefix and last newline lives inside do
+	errAppended := errUserAlreadyExists.AppendErr(errChangeMail)
+	do("Append Test Error type", &errAppended, expectedErrorMessage, t)
+}
+
+func TestAppend(t *testing.T) {
+	errors.NewLine = true
+	errors.Prefix = "error: "
+
+	errChangeMailMsg := "Please change your mail addr"
+	expectedErrorMessage := errUserAlreadyExists.Format(userMail).Error() + errChangeMailMsg + getNewLine() // first Prefix and last newline lives inside do
+	errAppended := errUserAlreadyExists.Append(errChangeMailMsg)
+	do("Append Test string Message", &errAppended, expectedErrorMessage, t)
+}
+
+func TestNewLine(t *testing.T) {
+	errors.NewLine = false
+
+	errNoNewLine := errors.New(errMessage)
+	expected := errors.Prefix + expectedUserAlreadyExists
+	do("NewLine Test", errNoNewLine, expected, t)
+
+	errors.NewLine = true
+}
+
+func TestPrefix(t *testing.T) {
+	errors.Prefix = "MyPrefix: "
+
+	errUpdatedPrefix := errors.New(errMessage)
+	expected := errors.Prefix + expectedUserAlreadyExists + "\n"
+	do("Prefix Test with "+errors.Prefix, errUpdatedPrefix, expected, t)
+}