Merge pull request #327 from jveski/issue-155

Clarify assert.Equal failure message given mismatched numeric types

assert/assertions.go

@@ -278,14 +278,47 @@ func Equal(t TestingT, expected, actual interface{}, msgAndArgs ...interface{})
 
 	if !ObjectsAreEqual(expected, actual) {
 		diff := diff(expected, actual)
-		return Fail(t, fmt.Sprintf("Not equal: %#v (expected)\n"+
-			"        != %#v (actual)%s", expected, actual, diff), msgAndArgs...)
+		expected, actual = formatUnequalValues(expected, actual)
+		return Fail(t, fmt.Sprintf("Not equal: %s (expected)\n"+
+			"        != %s (actual)%s", expected, actual, diff), msgAndArgs...)
 	}
 
 	return true
 
 }
 
+// formatUnequalValues takes two values of arbitrary types and returns string
+// representations appropriate to be presented to the user.
+//
+// If the values are not of like type, the returned strings will be prefixed
+// with the type name, and the value will be enclosed in parenthesis similar
+// to a type conversion in the Go grammar.
+func formatUnequalValues(expected, actual interface{}) (e string, a string) {
+	aType := reflect.TypeOf(expected)
+	bType := reflect.TypeOf(actual)
+
+	if aType != bType && isNumericType(aType) && isNumericType(bType) {
+		return fmt.Sprintf("%v(%#v)", aType, expected),
+			fmt.Sprintf("%v(%#v)", bType, actual)
+	}
+
+	return fmt.Sprintf("%#v", expected),
+		fmt.Sprintf("%#v", actual)
+}
+
+func isNumericType(t reflect.Type) bool {
+	switch t.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return true
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return true
+	case reflect.Float32, reflect.Float64:
+		return true
+	}
+
+	return false
+}
+
 // EqualValues asserts that two objects are equal or convertable to the same types
 // and equal.
 //

assert/assertions_test.go

@@ -195,6 +195,28 @@ func TestEqual(t *testing.T) {
 
 }
 
+func TestFormatUnequalValues(t *testing.T) {
+	expected, actual := formatUnequalValues("foo", "bar")
+	Equal(t, `"foo"`, expected, "value should not include type")
+	Equal(t, `"bar"`, actual, "value should not include type")
+
+	expected, actual = formatUnequalValues(123, 123)
+	Equal(t, `123`, expected, "value should not include type")
+	Equal(t, `123`, actual, "value should not include type")
+
+	expected, actual = formatUnequalValues(int64(123), int32(123))
+	Equal(t, `int64(123)`, expected, "value should include type")
+	Equal(t, `int32(123)`, actual, "value should include type")
+
+	type testStructType struct {
+		Val string
+	}
+
+	expected, actual = formatUnequalValues(&testStructType{Val: "test"}, &testStructType{Val: "test"})
+	Equal(t, `&assert.testStructType{Val:"test"}`, expected, "value should not include type annotation")
+	Equal(t, `&assert.testStructType{Val:"test"}`, actual, "value should not include type annotation")
+}
+
 func TestNotNil(t *testing.T) {
 
 	mockT := new(testing.T)