Allow fail to work in try/catch

package.json

@@ -103,6 +103,10 @@
     "watchPlugins": [
       "jest-watch-typeahead/filename",
       "jest-watch-typeahead/testname"
+    ],
+    "reporters": [
+      "<rootDir>/test/reporters/ExceptionlessExpectedFailureReporter.js",
+      "default"
     ]
   },
   "babel": {

src/matchers/fail.js

@@ -1,4 +1,5 @@
 export function fail(_, message) {
+  this.dontThrow();
   return {
     pass: false,
     message: () => (message ? message : 'fails by .fail() assertion'),

test/matchers/fail.test.js

@@ -1,13 +1,19 @@
 import * as matcher from 'src/matchers/fail';
 
 expect.extend(matcher);
-
 describe('.fail', () => {
   test('fails without message', () => {
-    expect(() => expect().fail()).toThrowErrorMatchingSnapshot();
+    expect().fail(); // This should fail!
   });
   test('fails with message', () => {
-    expect(() => expect().fail("This shouldn't fail!")).toThrowErrorMatchingSnapshot();
+    expect().fail('This should fail!');
+  });
+  test('fails when invoked in a try/catch', () => {
+    try {
+      expect().fail();
+    } catch (error) {
+      expect('this assertion').toBe('not checked');
+    }
   });
 });
 
@@ -16,6 +22,6 @@ describe('.not.fail', () => {
     expect().not.fail();
   });
   test('does not fail with message', () => {
-    expect().not.fail('this should fail!');
+    expect().not.fail('this should not fail!');
   });
 });

test/reporters/ExceptionlessExpectedFailureReporter.js

@@ -0,0 +1,83 @@
+/**
+ * Flips the test results for fail.test.js > .fail > <test cases>
+ */
+class ExceptionlessExpectedFailureReporter {
+  constructor(globalConfig, reporterOptions, reporterContext) {
+    this._globalConfig = globalConfig;
+    this._options = reporterOptions;
+    this._context = reporterContext;
+  }
+  onTestCaseResult(test, testCaseResult) {
+    this._processTestCaseResult(testCaseResult);
+  }
+  onTestFileResult(test, testResult, results) {
+    if (testResult.testFilePath.endsWith('fail.test.js')) {
+      this._processTestResults(results);
+    }
+  }
+  _processTestResults(results) {
+    for (let testSuiteResult of results.testResults) {
+      if (testSuiteResult.testFilePath.endsWith('fail.test.js')) {
+        let switchedToFailing = 0;
+        let switchedToPassing = 0;
+        for (let testCaseResult of testSuiteResult.testResults) {
+          const processResult = this._processTestCaseResult(testCaseResult);
+          if (processResult === 'switch-to-failing') switchedToFailing++;
+          if (processResult === 'switch-to-passing') switchedToPassing++;
+        }
+        const originalFailureCount = testSuiteResult.numFailingTests;
+        testSuiteResult.numFailingTests += switchedToFailing - switchedToPassing;
+        results.numFailedTests += switchedToFailing - switchedToPassing;
+        testSuiteResult.numPassingTests += switchedToPassing - switchedToFailing;
+        results.numPassedTests += switchedToPassing - switchedToFailing;
+        if (originalFailureCount === switchedToPassing) {
+          testSuiteResult.failureMessage = '';
+          results.numFailedTestSuites -= 1;
+          results.numPassedTestSuites += 1;
+          if (results.numFailedTestSuites === 0) results.success = true;
+          console.log('marking failing test suite as passing', testSuiteResult.testFilePath);
+        }
+      }
+    }
+  }
+
+  _processTestCaseResult(testCaseResult) {
+    if (this._hasDotFailAncestor(testCaseResult)) {
+      if (testCaseResult.status === 'failed') {
+        this._markPassing(testCaseResult);
+        return 'switch-to-passing';
+      } else if (testCaseResult.status === 'passed') {
+        this._markFailing(testCaseResult);
+        return 'switch-to-failing';
+      }
+    }
+    return 'unchanged';
+  }
+  _hasDotFailAncestor(result) {
+    return result.ancestorTitles.length > 0 && result.ancestorTitles[0] === '.fail';
+  }
+  _markPassing(result) {
+    result.status = 'passed';
+    result.failureDetails = [];
+    result.failureMessages = [];
+    result.numPassingAsserts = 1;
+  }
+  _markFailing(result) {
+    const message = `${result.fullName} was expected to fail, but did not.`;
+    result.status = 'failed';
+    result.failureDetails = [
+      {
+        matcherResult: {
+          pass: false,
+          message: message,
+        },
+        message: message,
+        stack: `${message}\n\tNo stack trace.\n\tThis is a placeholder message generated inside ExceptionlessExpectedFailureReporter`,
+      },
+    ];
+    result.failureMessages = [message];
+    result.numPassingAsserts = 0;
+  }
+}
+
+module.exports = ExceptionlessExpectedFailureReporter;