feat: add debug to render helpers for easier console debugging

README.md

@@ -139,6 +139,33 @@ Unmount the in-memory tree, triggering the appropriate lifecycle events
 
 When using React context providers, like Redux Provider, you'll likely want to wrap rendered component with them. In such cases it's convenient to create your custom `render` method. [Follow this great guide on how to set this up](https://github.com/kentcdodds/react-testing-library#custom-render).
 
+### `debug: (message?: string) => void`
+
+Prints deeply rendered component passed to `render` with optional message on top. Uses [debug.deep](#debug) under the hood, but it's easier to use.
+
+```jsx
+const { debug } = render(<Component />);
+
+debug('optional message');
+```
+
+logs optional message and colored JSX:
+
+```jsx
+optional message
+
+<TouchableOpacity
+  activeOpacity={0.2}
+  onPress={[Function bound fn]}
+>
+  <Text>Press me</Text>
+</TouchableOpacity>
+```
+
+### `debug.shallow: (message?: string) => void`
+
+Prints shallowly rendered component passed to `render` with optional message on top. Uses [debug.shallow](#debug) under the hood, but it's easier to use.
+
 ### `toJSON: () => ?ReactTestRendererJSON`
 
 Get the rendered component JSON representation, e.g. for snapshot testing.

src/__tests__/__snapshots__/render.test.js.snap

@@ -1,5 +1,143 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`debug 1`] = `
+"<View>
+  <Text>
+    Is the banana fresh?
+  </Text>
+  <Text
+    testID=\\"bananaFresh\\"
+  >
+    not fresh
+  </Text>
+  <View
+    accessible={true}
+    isTVSelectable={true}
+    onResponderGrant={[Function bound touchableHandleResponderGrant]}
+    onResponderMove={[Function bound touchableHandleResponderMove]}
+    onResponderRelease={[Function bound touchableHandleResponderRelease]}
+    onResponderTerminate={[Function bound touchableHandleResponderTerminate]}
+    onResponderTerminationRequest={[Function bound touchableHandleResponderTerminationRequest]}
+    onStartShouldSetResponder={[Function bound touchableHandleStartShouldSetResponder]}
+    style={
+      Object {
+        \\"opacity\\": 1,
+      }
+    }
+  >
+    <Text>
+      Change freshness!
+    </Text>
+  </View>
+</View>"
+`;
+
+exports[`debug changing component: bananaFresh button message should now be "fresh" 1`] = `
+"<View>
+  <Text>
+    Is the banana fresh?
+  </Text>
+  <Text
+    testID=\\"bananaFresh\\"
+  >
+    fresh
+  </Text>
+  <View
+    accessible={true}
+    isTVSelectable={true}
+    onResponderGrant={[Function bound touchableHandleResponderGrant]}
+    onResponderMove={[Function bound touchableHandleResponderMove]}
+    onResponderRelease={[Function bound touchableHandleResponderRelease]}
+    onResponderTerminate={[Function bound touchableHandleResponderTerminate]}
+    onResponderTerminationRequest={[Function bound touchableHandleResponderTerminationRequest]}
+    onStartShouldSetResponder={[Function bound touchableHandleStartShouldSetResponder]}
+    style={
+      Object {
+        \\"opacity\\": 1,
+      }
+    }
+  >
+    <Text>
+      Change freshness!
+    </Text>
+  </View>
+</View>"
+`;
+
+exports[`debug: shallow 1`] = `
+"<View>
+  <Text>
+    Is the banana fresh?
+  </Text>
+  <Text
+    testID=\\"bananaFresh\\"
+  >
+    not fresh
+  </Text>
+  <Button
+    onPress={[Function anonymous]}
+    type=\\"primary\\"
+  >
+    Change freshness!
+  </Button>
+</View>"
+`;
+
+exports[`debug: shallow with message 1`] = `
+"my other custom message
+
+<View>
+  <Text>
+    Is the banana fresh?
+  </Text>
+  <Text
+    testID=\\"bananaFresh\\"
+  >
+    not fresh
+  </Text>
+  <Button
+    onPress={[Function anonymous]}
+    type=\\"primary\\"
+  >
+    Change freshness!
+  </Button>
+</View>"
+`;
+
+exports[`debug: with message 1`] = `
+"my custom message
+
+<View>
+  <Text>
+    Is the banana fresh?
+  </Text>
+  <Text
+    testID=\\"bananaFresh\\"
+  >
+    not fresh
+  </Text>
+  <View
+    accessible={true}
+    isTVSelectable={true}
+    onResponderGrant={[Function bound touchableHandleResponderGrant]}
+    onResponderMove={[Function bound touchableHandleResponderMove]}
+    onResponderRelease={[Function bound touchableHandleResponderRelease]}
+    onResponderTerminate={[Function bound touchableHandleResponderTerminate]}
+    onResponderTerminationRequest={[Function bound touchableHandleResponderTerminationRequest]}
+    onStartShouldSetResponder={[Function bound touchableHandleStartShouldSetResponder]}
+    style={
+      Object {
+        \\"opacity\\": 1,
+      }
+    }
+  >
+    <Text>
+      Change freshness!
+    </Text>
+  </View>
+</View>"
+`;
+
 exports[`toJSON 1`] = `
 <View
   accessible={true}

src/__tests__/debug.test.js

@@ -4,6 +4,7 @@ import React from 'react';
 import { TouchableOpacity, Text } from 'react-native';
 import stripAnsi from 'strip-ansi';
 import { debug, render, fireEvent, flushMicrotasksQueue } from '..';
+import debugShallow from '../helpers/debugShallow';
 
 function TextComponent({ text }) {
   return <Text>{text}</Text>;
@@ -43,11 +44,11 @@ test('debug', () => {
 
   debug(component, 'test message');
 
-  expect(console.log).toBeCalledWith(output, 'test message');
+  expect(console.log).toBeCalledWith('test message\n\n', output);
 });
 
 test('debug.shallow', () => {
-  expect(debug.shallow).toBe(debug);
+  expect(debug.shallow).toBe(debugShallow);
 });
 
 test('debug.deep', () => {
@@ -65,7 +66,7 @@ test('debug.deep', () => {
 
   debug.deep(component, 'test message');
 
-  expect(console.log).toBeCalledWith(output, 'test message');
+  expect(console.log).toBeCalledWith('test message\n\n', output);
 });
 
 test('debug.deep async test', async () => {

src/__tests__/render.test.js

@@ -2,7 +2,8 @@
 /* eslint-disable react/no-multi-comp */
 import React from 'react';
 import { View, Text, TouchableOpacity } from 'react-native';
-import { render } from '..';
+import stripAnsi from 'strip-ansi';
+import { render, fireEvent } from '..';
 
 class Button extends React.Component<*> {
   render() {
@@ -172,3 +173,43 @@ test('toJSON', () => {
 
   expect(toJSON()).toMatchSnapshot();
 });
+
+test('debug', () => {
+  jest.spyOn(console, 'log').mockImplementation(x => x);
+
+  const { debug } = render(<Banana />);
+
+  debug();
+  debug('my custom message');
+  debug.shallow();
+  debug.shallow('my other custom message');
+
+  // eslint-disable-next-line no-console
+  const mockCalls = console.log.mock.calls;
+
+  expect(stripAnsi(mockCalls[0][0])).toMatchSnapshot();
+  expect(stripAnsi(mockCalls[1][0] + mockCalls[1][1])).toMatchSnapshot(
+    'with message'
+  );
+  expect(stripAnsi(mockCalls[2][0])).toMatchSnapshot('shallow');
+  expect(stripAnsi(mockCalls[3][0] + mockCalls[3][1])).toMatchSnapshot(
+    'shallow with message'
+  );
+});
+
+test('debug changing component', () => {
+  jest.spyOn(console, 'log').mockImplementation(x => x);
+
+  const { getByProps, debug } = render(<Banana />);
+
+  fireEvent.press(getByProps({ type: 'primary' }));
+
+  debug();
+
+  // eslint-disable-next-line no-console
+  const mockCalls = console.log.mock.calls;
+
+  expect(stripAnsi(mockCalls[4][0])).toMatchSnapshot(
+    'bananaFresh button message should now be "fresh"'
+  );
+});

src/debug.js

@@ -1,26 +1,15 @@
 // @flow
 /* eslint-disable no-console */
 import * as React from 'react';
-import prettyFormat, { plugins } from 'pretty-format';
-import shallow from './shallow';
 import render from './render';
-
-/**
- * Log pretty-printed shallow test component instance
- */
-function debugShallow(
-  instance: ReactTestInstance | React.Element<*>,
-  message?: any
-) {
-  const { output } = shallow(instance);
-
-  console.log(format(output), message || '');
-}
+import debugShallow from './helpers/debugShallow';
+import debugDeep from './helpers/debugDeep';
+import format from './helpers/format';
 
 /**
  * Log pretty-printed deep test component instance
  */
-function debugDeep(
+function debugDeepElementOrInstance(
   instance: React.Element<*> | ?ReactTestRendererJSON,
   message?: any = ''
 ) {
@@ -29,21 +18,22 @@ function debugDeep(
     // rendering ?ReactTestRendererJSON
     // $FlowFixMe
     const { toJSON } = render(instance);
-    console.log(format(toJSON()), message);
+    if (message) {
+      console.log(`${message}\n\n`, format(toJSON()));
+    } else {
+      console.log(format(toJSON()));
+    }
   } catch (e) {
-    console.log(format(instance), message);
+    // $FlowFixMe
+    debugDeep(instance);
   }
 }
 
-const format = input =>
-  prettyFormat(input, {
-    plugins: [plugins.ReactTestComponent, plugins.ReactElement],
-    highlight: true,
-  });
-
-const debug = debugShallow;
+function debug(instance: ReactTestInstance | React.Element<*>, message?: any) {
+  return debugShallow(instance, message);
+}
 
 debug.shallow = debugShallow;
-debug.deep = debugDeep;
+debug.deep = debugDeepElementOrInstance;
 
 export default debug;

src/helpers/debugDeep.js

@@ -0,0 +1,16 @@
+// @flow
+import format from './format';
+
+/**
+ * Log pretty-printed deep test component instance
+ */
+export default function debugDeep(
+  instance: ?ReactTestRendererJSON,
+  message?: any = ''
+) {
+  if (message) {
+    console.log(`${message}\n\n`, format(instance));
+  } else {
+    console.log(format(instance));
+  }
+}

src/helpers/debugShallow.js

@@ -0,0 +1,20 @@
+// @flow
+import * as React from 'react';
+import shallow from '../shallow';
+import format from './format';
+
+/**
+ * Log pretty-printed shallow test component instance
+ */
+export default function debugShallow(
+  instance: ReactTestInstance | React.Element<*>,
+  message?: any
+) {
+  const { output } = shallow(instance);
+
+  if (message) {
+    console.log(`${message}\n\n`, format(output));
+  } else {
+    console.log(format(output));
+  }
+}

src/helpers/format.js

@@ -0,0 +1,10 @@
+// @flow
+import prettyFormat, { plugins } from 'pretty-format';
+
+const format = (input: ?ReactTestRendererJSON) =>
+  prettyFormat(input, {
+    plugins: [plugins.ReactTestComponent, plugins.ReactElement],
+    highlight: true,
+  });
+
+export default format;

src/render.js

@@ -3,6 +3,8 @@ import * as React from 'react';
 import TestRenderer from 'react-test-renderer'; // eslint-disable-line import/no-extraneous-dependencies
 import { getByAPI } from './helpers/getByAPI';
 import { queryByAPI } from './helpers/queryByAPI';
+import debugShallow from './helpers/debugShallow';
+import debugDeep from './helpers/debugDeep';
 
 /**
  * Renders test component deeply using react-test-renderer and exposes helpers
@@ -21,5 +23,14 @@ export default function render(
     update: renderer.update,
     unmount: renderer.unmount,
     toJSON: renderer.toJSON,
+    debug: debug(instance, renderer),
   };
 }
+
+function debug(instance: ReactTestInstance, renderer) {
+  function debugImpl(message?: string) {
+    return debugDeep(renderer.toJSON(), message);
+  }
+  debugImpl.shallow = message => debugShallow(instance, message);
+  return debugImpl;
+}