Add flow type tests

.flowconfig

@@ -0,0 +1,7 @@
+[ignore]
+<PROJECT_ROOT>/node_modules/.*
+<PROJECT_ROOT>/.*\.js$
+
+[options]
+emoji=true
+suppress_comment=\\(.\\|\n\\)*\\$ExpectError

index.js.flow

@@ -63,8 +63,8 @@ type AssertContext = {
 	};
 	// Assert that function doesn't throw an error or promise resolves.
 	notThrows: {
-		notThrows<U>(value: PromiseLike<U>, message?: string): Promise<U>;
-		notThrows(value: () => mixed, message?: string): void;
+		<U>(value: PromiseLike<U>, message?: string): Promise<U>;
+		(value: () => mixed, message?: string): void;
 	};
 	// Assert that contents matches regex.
 	regex(contents: string, regex: RegExp, message?: string): void;

package.json

@@ -43,7 +43,7 @@
     "node": ">=4"
   },
   "scripts": {
-    "test": "xo && nyc tap --no-cov --timeout=150 --jobs=4 test/*.js test/reporters/*.js",
+    "test": "xo && flow check && nyc tap --no-cov --timeout=150 --jobs=4 test/*.js test/reporters/*.js",
     "test-win": "tap --no-cov --reporter=classic --timeout=150 --jobs=4 test/*.js test/reporters/*.js",
     "visual": "node test/visual/run-visual-tests.js",
     "prepublish": "npm run make-ts",
@@ -167,6 +167,7 @@
     "coveralls": "^2.11.4",
     "delay": "^1.3.0",
     "execa": "^0.6.0",
+    "flow-bin": "^0.38.0",
     "get-stream": "^3.0.0",
     "git-branch": "^0.3.0",
     "has-ansi": "^2.0.0",

test/flow-types/regression-1114.js.flow

@@ -0,0 +1,53 @@
+/* @flow */
+
+const test = require('../../');
+
+test('Named test', t => {
+	t.pass('Success');
+	// $ExpectError: Unknown method "unknownAssertion"
+	t.unknownAssertion('Whoops');
+	const context = t.context;
+	// $ExpectError: Unknown method "end"
+	t.end();
+});
+
+test(t => {
+	t.pass('Success');
+	// $ExpectError: Unknown method "unknownAssertion"
+	t.unknownAssertion('Whoops');
+	const context = t.context;
+	// $ExpectError: Unknown method "end"
+	t.end();
+});
+
+test.cb(t => {
+	t.pass('Success');
+	t.end();
+});
+
+test.beforeEach(t => {
+	// $ExpectError: Unknown property "context"
+	const context = t.context;
+})
+
+function macro(t, input, expected) {
+	t.is(eval(input), expected);
+}
+macro.title = (title, input, expected) => title || input;
+
+function macro2(t, input, expected) {
+	t.is(eval(input), expected);
+}
+
+test('2 + 2 === 4', macro, '2 + 2', 4);
+test(macro, '2 * 3', 6);
+
+test('2 + 2 === 4', [macro, macro2], '2 + 2', 4);
+test([macro, macro2], '2 * 3', 6);
+
+function macroBadTitle(t, input, expected) {
+	t.is(eval(input), expected);
+}
+macroBadTitle.title = 'Not a function';
+// $ExpectError: Macro "title" is not a function
+test('2 + 2 === 4', macroBadTitle, '2 + 2', 4);

test/flow-types/regression-1148.js.flow

@@ -0,0 +1,19 @@
+/* @flow */
+
+const test = require('../../');
+
+test(t => {
+	t.throws(() => { throw new Error(); });
+	t.throws(Promise.reject(new Error()));
+
+	t.notThrows(() => { return; });
+	t.notThrows(Promise.resolve('Success'));
+
+	const error = t.throws(() => { throw new Error(); });
+	const message: string = error.message;
+
+	const promise = t.throws(Promise.reject(new Error()));
+	promise.then(error => {
+		const message: string = error.message;
+	})
+});