Allowed named classes and functions as BlockNames (jestjs#5154)

* Allowed named classes and functions as BlockNames

describe can now take in classes and functions as the names.

* Added integration test for describe with a class or function

* Corrected globals.test.js.snap

* Mentioned changes in CHANGELOG.md

* Master!

* Added failure for non-string/class/function

* I am become pretty

* Fixed failure message for globals.test.js.snap

* Removed error test case for array-as-descriptor

* Removed error test for array-as-descriptor

* Added allowance for numbers as test descriptors

* Prettier...

CHANGELOG.md

@@ -7,6 +7,8 @@
 
 ### Features
 
+* `[jest-jasmine]` Allowed classes and functions as `describe` names
+  ([#5154](https://github.com/facebook/jest/pull/5154))
 * `[jest-jasmine2]` Support generator functions as specs.
   ([#5166](https://github.com/facebook/jest/pull/5166))
 

integration_tests/__tests__/__snapshots__/globals.test.js.snap

@@ -156,3 +156,20 @@ Time:        <<REPLACED>>
 Ran all test suites.
 "
 `;
+
+exports[`function as descriptor 1`] = `
+"PASS __tests__/function-as-descriptor.test.js
+  Foo
+    ✓ it
+
+"
+`;
+
+exports[`function as descriptor 2`] = `
+"Test Suites: 1 passed, 1 total
+Tests:       1 passed, 1 total
+Snapshots:   0 total
+Time:        <<REPLACED>>
+Ran all test suites.
+"
+`;

integration_tests/__tests__/globals.test.js

@@ -204,3 +204,21 @@ test('tests with no implementation with expand arg', () => {
   expect(rest).toMatchSnapshot();
   expect(summary).toMatchSnapshot();
 });
+
+test('function as descriptor', () => {
+  const filename = 'function-as-descriptor.test.js';
+  const content = `
+    function Foo() {}
+    describe(Foo, () => {
+      it('it', () => {});
+    });
+  `;
+
+  writeFiles(TEST_DIR, {[filename]: content});
+  const {stderr, status} = runJest(DIR);
+  expect(status).toBe(0);
+
+  const {summary, rest} = extractSummary(stderr);
+  expect(rest).toMatchSnapshot();
+  expect(summary).toMatchSnapshot();
+});

packages/jest-jasmine2/src/jasmine/Suite.js

@@ -38,7 +38,7 @@ import expectationResultFactory from '../expectation_result_factory';
 export default function Suite(attrs: Object) {
   this.id = attrs.id;
   this.parentSuite = attrs.parentSuite;
-  this.description = attrs.description;
+  this.description = convertDescriptorToString(attrs.description);
   this.throwOnExpectationFailure = !!attrs.throwOnExpectationFailure;
 
   this.beforeFns = [];
@@ -181,6 +181,33 @@ Suite.prototype.addExpectationResult = function() {
   }
 };
 
+function convertDescriptorToString(descriptor) {
+  if (
+    typeof descriptor === 'string' ||
+    typeof descriptor === 'number' ||
+    descriptor === undefined
+  ) {
+    return descriptor;
+  }
+
+  if (typeof descriptor !== 'function') {
+    throw new Error('describe expects a class, function, number, or string.');
+  }
+
+  if (descriptor.name !== undefined) {
+    return descriptor.name;
+  }
+
+  const stringified = descriptor.toString();
+  const typeDescriptorMatch = stringified.match(/class|function/);
+  const indexOfNameSpace =
+    typeDescriptorMatch.index + typeDescriptorMatch[0].length;
+  const indexOfNameAfterSpace = stringified.search(/\(|\{/, indexOfNameSpace);
+  const name = stringified.substring(indexOfNameSpace, indexOfNameAfterSpace);
+
+  return name.trim();
+}
+
 function isAfterAll(children) {
   return children && children[0].result.status;
 }

types/Circus.js

@@ -9,7 +9,7 @@
 
 export type DoneFn = (reason?: string | Error) => void;
 export type BlockFn = () => void;
-export type BlockName = string;
+export type BlockName = string | Function;
 export type BlockMode = void | 'skip' | 'only';
 export type TestMode = BlockMode;
 export type TestName = string;