Add support for %p pretty format placeholder

e2e/__tests__/__snapshots__/each.test.js.snap

@@ -1,5 +1,24 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`formats args with pretty format when given %p 1`] = `
+"PASS __tests__/pretty.test.js
+  ✓ \\"hello\\" == \\"hello\\"
+  ✓ 1 == 1
+  ✓ null == null
+  ✓ undefined == undefined
+  ✓ 1.2 == 1.2
+  ✓ {\\"foo\\": \\"bar\\"} == {\\"foo\\": \\"bar\\"}
+  ✓ {\\"foo\\": [Object]} == {\\"foo\\": [Object]}
+  ✓ [Function noop] == [Function noop]
+  ✓ [] == []
+  ✓ [[Object]] == [[Object]]
+  ✓ Infinity == Infinity
+  ✓ -Infinity == -Infinity
+  ✓ NaN == NaN
+
+"
+`;
+
 exports[`runs only the describe.only.each tests 1`] = `
 "PASS __tests__/describe-only.test.js
   passes all rows expected true == true

e2e/__tests__/each.test.js

@@ -56,3 +56,10 @@ test('runs only the describe.only.each tests', () => {
   expect(rest).toMatchSnapshot();
   expect(result.status).toBe(0);
 });
+
+test('formats args with pretty format when given %p', () => {
+  const result = runJest(dir, ['pretty.test.js']);
+  const {rest} = extractSummary(result.stderr);
+  expect(rest).toMatchSnapshot();
+  expect(result.status).toBe(0);
+});

e2e/each/__tests__/pretty.test.js

@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2018-present, Facebook, Inc. All rights reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+const noop = () => {};
+
+it.each([
+  ['hello', 'hello'],
+  [1, 1],
+  [null, null],
+  [undefined, undefined],
+  [1.2, 1.2],
+  [{foo: 'bar'}, {foo: 'bar'}],
+  [{foo: {bar: 'baz'}}, {foo: {bar: 'baz'}}],
+  [noop, noop],
+  [[], []],
+  [[{foo: {bar: 'baz'}}], [{foo: {bar: 'baz'}}]],
+  [Infinity, Infinity],
+  [-Infinity, -Infinity],
+  [NaN, NaN],
+])('%p == %p', (left, right) => {
+  expect(left).toEqual(right);
+});

packages/jest-each/src/__tests__/array.test.js

@@ -6,6 +6,7 @@
  *
  */
 
+import pretty from 'pretty-format';
 import each from '../';
 
 const noop = () => {};
@@ -140,6 +141,52 @@ describe('jest-each', () => {
         );
       });
 
+      test('calls global test title with %p placeholder injected at the correct positions', () => {
+        const globalTestMocks = getGlobalTestMocks();
+        const eachObject = each.withGlobal(globalTestMocks)([
+          ['string1', 'pretty1', 'string2', 'pretty2'],
+          ['string1', 'pretty1', 'string2', 'pretty2'],
+        ]);
+        const testFunction = get(eachObject, keyPath);
+        testFunction('expected string: %s %p %s %p', noop);
+
+        const globalMock = get(globalTestMocks, keyPath);
+        expect(globalMock).toHaveBeenCalledTimes(2);
+        expect(globalMock).toHaveBeenCalledWith(
+          `expected string: string1 ${pretty('pretty1')} string2 ${pretty(
+            'pretty2',
+          )}`,
+          expectFunction,
+        );
+        expect(globalMock).toHaveBeenCalledWith(
+          `expected string: string1 ${pretty('pretty1')} string2 ${pretty(
+            'pretty2',
+          )}`,
+          expectFunction,
+        );
+      });
+
+      test('does not calls global test title with %p placeholder when no data is supplied at given position', () => {
+        const globalTestMocks = getGlobalTestMocks();
+        const eachObject = each.withGlobal(globalTestMocks)([
+          ['string1', 'pretty1', 'string2'],
+          ['string1', 'pretty1', 'string2'],
+        ]);
+        const testFunction = get(eachObject, keyPath);
+        testFunction('expected string: %s %p %s %p', noop);
+
+        const globalMock = get(globalTestMocks, keyPath);
+        expect(globalMock).toHaveBeenCalledTimes(2);
+        expect(globalMock).toHaveBeenCalledWith(
+          `expected string: string1 ${pretty('pretty1')} string2 %p`,
+          expectFunction,
+        );
+        expect(globalMock).toHaveBeenCalledWith(
+          `expected string: string1 ${pretty('pretty1')} string2 %p`,
+          expectFunction,
+        );
+      });
+
       test('calls global with cb function containing all parameters of each test case when given 1d array', () => {
         const globalTestMocks = getGlobalTestMocks();
         const testCallBack = jest.fn();

packages/jest-each/src/bind.js

@@ -12,10 +12,15 @@ import chalk from 'chalk';
 import pretty from 'pretty-format';
 
 type Table = Array<Array<any>>;
+type PrettyArgs = {
+  args: Array<mixed>,
+  title: string,
+};
 
 const EXPECTED_COLOR = chalk.green;
 const RECEIVED_COLOR = chalk.red;
-const SUPPORTED_PLACEHOLDERS = /%[sdifjoO%]/g;
+const SUPPORTED_PLACEHOLDERS = /%[sdifjoOp%]/g;
+const PRETTY_PLACEHOLDER = '%p';
 
 export default (cb: Function) => (...args: any) =>
   function eachBind(title: string, test: Function): void {
@@ -59,9 +64,41 @@ export default (cb: Function) => (...args: any) =>
     );
   };
 
-const arrayFormat = (str, ...args) => {
-  const matches = (str.match(SUPPORTED_PLACEHOLDERS) || []).length;
-  return util.format(str, ...args.slice(0, matches));
+const getPrettyIndexes = placeholders =>
+  placeholders.reduce(
+    (indexes, placeholder, index) =>
+      placeholder === PRETTY_PLACEHOLDER ? indexes.concat(index) : indexes,
+    [],
+  );
+
+const arrayFormat = (title, ...args) => {
+  const placeholders = title.match(SUPPORTED_PLACEHOLDERS) || [];
+  const prettyIndexes = getPrettyIndexes(placeholders);
+
+  const {title: prettyTitle, args: remainingArgs} = args.reduce(
+    (acc: PrettyArgs, arg, index) => {
+      if (prettyIndexes.indexOf(index) !== -1) {
+        return {
+          args: acc.args,
+          title: acc.title.replace(
+            PRETTY_PLACEHOLDER,
+            pretty(arg, {maxDepth: 1, min: true}),
+          ),
+        };
+      }
+
+      return {
+        args: acc.args.concat([arg]),
+        title: acc.title,
+      };
+    },
+    {args: [], title},
+  );
+
+  return util.format(
+    prettyTitle,
+    ...remainingArgs.slice(0, placeholders.length - prettyIndexes.length),
+  );
 };
 
 const applyRestParams = (params: Array<any>, test: Function) => {