soumya92/barista

// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/*
Package pango provides provides a method to test markup equality.
It compares to strings that represent pango markup while ignoring
differences in attribute order, escaping, etc.
*/
package pango

import (
    "fmt"
    "strings"
    "testing"

    "github.com/stretchr/testify/require"
    "golang.org/x/net/html"
)

// AssertEqual asserts that the given strings represent equivalent pango markup,
// i.e. the result of their rendering will be the same.
func AssertEqual(t *testing.T, expected, actual string, args ...interface{}) {
    expectedR, err := html.Parse(strings.NewReader(expected))
    require.NoError(t, err, args...)
    actualR, err := html.Parse(strings.NewReader(actual))
    require.NoError(t, err, args...)
    if !equalMarkup(expectedR, actualR) {
        require.Fail(t, fmt.Sprintf("%s !~= %s", expected, actual), args...)
    }
}

// AssertText asserts that the markup string has the expected text content.
// Text content ignores any tags and attributes, using only rendered text.
func AssertText(t *testing.T, expected string, markup string, args ...interface{}) {
    markupR, err := html.Parse(strings.NewReader(markup))
    require.NoError(t, err, args...)
    require.Equal(t, expected, textOf(markupR), args...)
}

func equalMarkup(a, b *html.Node) bool {
    if a == nil && b == nil {
        return true
    }
    if a == nil || b == nil {
        return false
    }
    if a.Data != b.Data {
        return false
    }
    if len(a.Attr) != len(b.Attr) {
        return false
    }
    aAttrMap := map[string]string{}
    for _, aAttr := range a.Attr {
        aAttrMap[aAttr.Key] = aAttr.Val
    }
    for _, bAttr := range b.Attr {
        if aAttrMap[bAttr.Key] != bAttr.Val {
            return false
        }
    }
    if !equalMarkup(a.NextSibling, b.NextSibling) {
        return false
    }
    if !equalMarkup(a.FirstChild, b.FirstChild) {
        return false
    }
    return true
}

func textOf(n *html.Node) (text string) {
    if n == nil {
        return text
    }
    if n.Type == html.TextNode {
        text += n.Data
    }
    text += textOf(n.FirstChild)
    text += textOf(n.NextSibling)
    return text
}