Added throwUnless and throwUnlessAsync

These are similar to `expect` and `expectAsync` except that they throw
exceptions rather than recording matcher failures as spec/suite failures.
They're intended to support using Jasmine matchers in testing-library's
`waitFor`, and also provide a way to integration-test custom matchers.

These funtions are not equivalent to `expect` and `expectAsync` and should
not be used in situations where you want a matcher failure to reliably fail
the spec. Whether that happens depends on the structure of the surrounding
code. In general, you should only use `throwUnless` when you expect
something (which could be your own code or library code like `waitFor`) to
catch the resulting exception.

Fixes #2003.
Fixes #1980.

src/core/requireInterface.js

@@ -225,6 +225,50 @@ getJasmineRequireObj().interface = function(jasmine, env) {
       return env.expectAsync(actual);
     },
 
+    /**
+     * Create an asynchronous expectation for a spec and throw an error if it fails.
+     *
+     * This is intended to allow Jasmine matchers to be used with tools like
+     * testing-library's `waitFor`, which expect matcher failures to throw
+     * exceptions and not trigger a spec failure if the exception is caught.
+     * It can also be used to integration-test custom matchers.
+     *
+     * If the resulting expectation fails, a {@link ThrowUnlessFailure} will be
+     * thrown. A failed expectation will not result in a spec failure unless the
+     * exception propagates back to Jasmine, either via the call stack or via
+     * the global unhandled exception/unhandled promise rejection events.
+     * @name throwUnlessAsync
+     * @param actual
+     * @global
+     * @param {Object} actual - Actual computed value to test expectations against.
+     * @return {matchers}
+     */
+    throwUnlessAsync: function(actual) {
+      return env.throwUnless(actual);
+    },
+
+    /**
+     * Create an expectation for a spec and throw an error if it fails.
+     *
+     * This is intended to allow Jasmine matchers to be used with tools like
+     * testing-library's `waitFor`, which expect matcher failures to throw
+     * exceptions and not trigger a spec failure if the exception is caught.
+     * It can also be used to integration-test custom matchers.
+     *
+     * If the resulting expectation fails, a {@link ThrowUnlessFailure} will be
+     * thrown. A failed expectation will not result in a spec failure unless the
+     * exception propagates back to Jasmine, either via the call stack or via
+     * the global unhandled exception/unhandled promise rejection events.
+     * @name throwUnless
+     * @param actual
+     * @global
+     * @param {Object} actual - Actual computed value to test expectations against.
+     * @return {matchers}
+     */
+    throwUnless: function(actual) {
+      return env.throwUnless(actual);
+    },
+
     /**
      * Mark a spec as pending, expectation results will be ignored.
      * @name pending