Support snapshot testing (#24)

* Add angular-snapshot serializer

* Add HTMLElementPlugin until Jest 20 release

* Add jest as a peer dep

* Update examples with snapshots

HTMLElementPlugin.js

@@ -0,0 +1,102 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+'use strict';
+
+function escapeHTML(str) {
+  return str.replace(/</g, '&lt;').replace(/>/g, '&gt;');
+}
+
+const HTML_ELEMENT_REGEXP = /(HTML\w*?Element)/;
+const test = isHTMLElement;
+
+function isHTMLElement(value) {
+  return (
+    value !== undefined &&
+    value !== null &&
+    value.nodeType === 1 &&
+    value.constructor !== undefined &&
+    HTML_ELEMENT_REGEXP.test(value.constructor.name)
+  );
+}
+
+function printChildren(flatChildren, print, indent, colors, opts) {
+  return flatChildren
+    .map(node => {
+      if (typeof node === 'object') {
+        return print(node, print, indent, colors, opts);
+      } else if (typeof node === 'string') {
+        return colors.content.open + escapeHTML(node) + colors.content.close;
+      } else {
+        return print(node);
+      }
+    })
+    .join(opts.edgeSpacing);
+}
+
+function printAttributes(attributes, print, indent, colors, opts) {
+  return attributes
+    .sort()
+    .map(attribute => {
+      return (
+        opts.spacing +
+        indent(colors.prop.open + attribute.name + colors.prop.close + '=') +
+        colors.value.open +
+        `"${attribute.value}"` +
+        colors.value.close
+      );
+    })
+    .join('');
+}
+
+const print = (
+  element,
+  print,
+  indent,
+  opts,
+  colors
+) => {
+  let result = colors.tag.open + '<';
+  const elementName = element.tagName.toLowerCase();
+  result += elementName + colors.tag.close;
+
+  const hasAttributes = element.attributes && element.attributes.length;
+  if (hasAttributes) {
+    const attributes = Array.prototype.slice.call(element.attributes);
+    result += printAttributes(attributes, print, indent, colors, opts);
+  }
+
+  const flatChildren = Array.prototype.slice.call(element.children);
+  if (!flatChildren.length && element.textContent) {
+    flatChildren.push(element.textContent.trim());
+  }
+
+  const closeInNewLine = hasAttributes && !opts.min;
+  if (flatChildren.length) {
+    const children = printChildren(flatChildren, print, indent, colors, opts);
+    result +=
+      colors.tag.open +
+      (closeInNewLine ? '\n' : '') +
+      '>' +
+      colors.tag.close +
+      (children && opts.edgeSpacing + indent(children) + opts.edgeSpacing) +
+      colors.tag.open +
+      '</' +
+      elementName +
+      '>' +
+      colors.tag.close;
+  } else {
+    result +=
+      colors.tag.open + (closeInNewLine ? '\n' : ' ') + '/>' + colors.tag.close;
+  }
+
+  return result;
+};
+
+module.exports = ({print, test});

angular-snapshot.js

@@ -0,0 +1,64 @@
+const printAttributes = (val, attributes, print, indent, colors, opts) => {
+  return attributes
+    .sort()
+    .map(attribute => {
+      return (
+        opts.spacing +
+        indent(colors.prop.open + attribute + colors.prop.close + '=') +
+        colors.value.open +
+        (val.componentInstance[attribute] &&
+          val.componentInstance[attribute].constructor
+          ? '{[Function ' +
+              val.componentInstance[attribute].constructor.name +
+              ']}'
+          : `"${val.componentInstance[attribute]}"`) +
+        colors.value.close
+      );
+    })
+    .join('');
+};
+
+const print = (val, print, indent, opts, colors) => {
+  let result = '';
+  let componentAttrs = '';
+
+  const componentName = val.componentRef._elDef.element.name;
+  const componentInstance = print(val.componentInstance);
+  const nodes = val.componentRef._view.nodes
+    .filter(node => node.hasOwnProperty('renderElement'))
+    .map(node => print(node.renderElement))
+    .join('\n');
+
+  const attributes = Object.keys(val.componentInstance);
+
+  if (attributes.length) {
+    componentAttrs += printAttributes(
+      val,
+      attributes,
+      print,
+      indent,
+      colors,
+      opts
+    );
+  }
+
+  return (
+    '<' +
+    componentName +
+    componentAttrs +
+    (componentAttrs.length ? '\n' : '') +
+    '>\n' +
+    indent(nodes) +
+    '\n</' +
+    componentName +
+    '>'
+  );
+};
+
+const test = val =>
+  val !== undefined &&
+  val !== null &&
+  typeof val === 'object' &&
+  Object.prototype.hasOwnProperty.call(val, 'componentRef');
+
+module.exports = {print, test};

circle.yml

@@ -1,6 +1,6 @@
 machine:
   environment:
-    YARN_VERSION: 0.20.3
+    YARN_VERSION: 0.22.0
     PATH: "${PATH}:${HOME}/.yarn/bin:${HOME}/${CIRCLE_PROJECT_REPONAME}/node_modules/.bin"
   node:
     version: 7
@@ -20,4 +20,4 @@ dependencies:
 test:
   override:
     - yarn run test:ci
-    - yarn link && cd example && yarn run test:ci && yarn run test:coverage
+    - yarn link && cd example && yarn link jest-preset-angular && yarn run test:ci && yarn run test:coverage

example/src/app/__snapshots__/app.component.spec.ts.snap

@@ -0,0 +1,17 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`AppComponent snaps 1`] = `
+<app-root
+  hasClass={[Function Boolean]}
+  title={[Function String]}
+>
+  <div
+    id="root1"
+    ng-version="4.0.1"
+  >
+    <h1>
+      <app-calc />
+    </h1>
+  </div>
+</app-root>
+`;

example/src/app/app.component.html

@@ -1,3 +1,6 @@
 <h1>
   {{title}}
+  <app-calc
+    [hasAClass]="hasClass"
+  ></app-calc>
 </h1>

example/src/app/app.component.spec.ts

@@ -1,5 +1,6 @@
 import { TestBed, async } from '@angular/core/testing';
-
+import { NO_ERRORS_SCHEMA } from '@angular/core';
+import { CalcComponent } from 'app/calc/calc.component';
 import { AppComponent } from './app.component';
 
 describe('AppComponent', () => {
@@ -8,6 +9,7 @@ describe('AppComponent', () => {
       declarations: [
         AppComponent
       ],
+      schemas: [NO_ERRORS_SCHEMA]
     }).compileComponents();
   }));
 
@@ -17,6 +19,11 @@ describe('AppComponent', () => {
     expect(app).toBeTruthy();
   }));
 
+  it('snaps', () => {
+    const fixture = TestBed.createComponent(AppComponent);
+    expect(fixture).toMatchSnapshot();
+  })
+
   it(`should have as title 'app works!'`, async(() => {
     const fixture = TestBed.createComponent(AppComponent);
     const app = fixture.debugElement.componentInstance;

example/src/app/app.component.ts

@@ -7,4 +7,5 @@ import { Component } from '@angular/core';
 })
 export class AppComponent {
   title = 'app works!';
+  hasClass = true;
 }

example/src/app/calc/__snapshots__/calc.component.spec.ts.snap

@@ -0,0 +1,20 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`CalcComponent should snap 1`] = `
+<app-calc
+  prop1={[Function Number]}
+>
+  <div
+    id="root0"
+    ng-version="4.0.1"
+  >
+    <p
+      class="a-default-class"
+      ng-reflect-klass="a-default-class"
+      ng-reflect-ng-class="[object Object]"
+    >
+      calc works!
+    </p>
+  </div>
+</app-calc>
+`;

example/src/app/calc/calc.component.html

@@ -1,3 +1,8 @@
-<p>
+<p
+  class="a-default-class"
+  [ngClass]="{
+    'a-class': hasAClass
+  }"
+>
   calc works!
 </p>

example/src/app/calc/calc.component.spec.ts

@@ -8,9 +8,9 @@ describe('CalcComponent', () => {
 
   beforeEach(async(() => {
     TestBed.configureTestingModule({
-      declarations: [ CalcComponent ]
+      declarations: [CalcComponent]
     })
-    .compileComponents();
+      .compileComponents();
   }));
 
   beforeEach(() => {
@@ -19,7 +19,7 @@ describe('CalcComponent', () => {
     fixture.detectChanges();
   });
 
-  it('should create', () => {
-    expect(component).toBeTruthy();
+  it('should snap', () => {
+    expect(fixture).toMatchSnapshot();
   });
 });

example/src/app/calc/calc.component.ts

@@ -1,15 +1,25 @@
-import { Component, OnInit } from '@angular/core';
+import { Component, OnInit, Input } from '@angular/core';
+import { Observable } from 'rxjs/Observable';
 
 @Component({
   selector: 'app-calc',
   templateUrl: './calc.component.html',
   styleUrls: ['./calc.component.css']
 })
 export class CalcComponent implements OnInit {
+  @Input() hasAClass;
+  prop1: number;
+  observable$: Observable<string>;
 
-  constructor() { }
+  constructor() {
+    this.init();
+    this.prop1 = 1337;
+  }
 
   ngOnInit() {
   }
 
+  init() {
+    return 'Imma method';
+  }
 }

package.json

@@ -14,6 +14,9 @@
     "jest": "^19.0.2",
     "typescript": "^2.2.2"
   },
+  "peerDependencies": {
+    "jest": "^19.0.2"
+  },
   "scripts": {
     "test": "jest",
     "test:ci": "jest -i"

setupJest.js

@@ -6,6 +6,8 @@ require('zone.js/dist/sync-test');
 require('zone.js/dist/async-test');
 require('zone.js/dist/fake-async-test');
 require('jest-zone-patch');
+const angularSnapshot = require('./angular-snapshot');
+const HTMLElementPlugin = require('./HTMLElementPlugin');
 const { getTestBed } = require('@angular/core/testing');
 const {
   BrowserDynamicTestingModule,
@@ -16,3 +18,6 @@ getTestBed().initTestEnvironment(
   BrowserDynamicTestingModule,
   platformBrowserDynamicTesting()
 );
+
+expect.addSnapshotSerializer(HTMLElementPlugin);
+expect.addSnapshotSerializer(angularSnapshot);