Typecheck arguments to t.regex() and t.notRegex()

lib/assert.js

@@ -300,6 +300,21 @@ function wrapAssertions(callbacks) {
 		},
 
 		regex(string, regex, message) {
+			if (typeof string !== 'string') {
+				throw new AssertionError({
+					assertion: 'regex',
+					message: '`t.regex()` must be called with a string',
+					values: [formatAssertError.formatWithLabel('Called with:', string)]
+				});
+			}
+			if (!(regex instanceof RegExp)) {
+				throw new AssertionError({
+					assertion: 'regex',
+					message: '`t.regex()` must be called with a regular expression',
+					values: [formatAssertError.formatWithLabel('Called with:', regex)]
+				});
+			}
+
 			if (!regex.test(string)) {
 				throw new AssertionError({
 					assertion: 'regex',
@@ -313,6 +328,21 @@ function wrapAssertions(callbacks) {
 		},
 
 		notRegex(string, regex, message) {
+			if (typeof string !== 'string') {
+				throw new AssertionError({
+					assertion: 'notRegex',
+					message: '`t.notRegex()` must be called with a string',
+					values: [formatAssertError.formatWithLabel('Called with:', string)]
+				});
+			}
+			if (!(regex instanceof RegExp)) {
+				throw new AssertionError({
+					assertion: 'notRegex',
+					message: '`t.notRegex()` must be called with a regular expression',
+					values: [formatAssertError.formatWithLabel('Called with:', regex)]
+				});
+			}
+
 			if (regex.test(string)) {
 				throw new AssertionError({
 					assertion: 'notRegex',

test/assert.js

@@ -808,6 +808,26 @@ test('.regex()', t => {
 	t.end();
 });
 
+test('.regex() fails if passed a bad value', t => {
+	failsWith(t, () => {
+		assertions.regex(42, /foo/);
+	}, {
+		assertion: 'regex',
+		message: '`t.regex()` must be called with a string',
+		values: [{label: 'Called with:', formatted: /42/}]
+	});
+
+	failsWith(t, () => {
+		assertions.regex('42', {});
+	}, {
+		assertion: 'regex',
+		message: '`t.regex()` must be called with a regular expression',
+		values: [{label: 'Called with:', formatted: /Object/}]
+	});
+
+	t.end();
+});
+
 test('.notRegex()', t => {
 	passes(t, () => {
 		assertions.notRegex('abc', /def/);
@@ -837,3 +857,23 @@ test('.notRegex()', t => {
 
 	t.end();
 });
+
+test('.notRegex() fails if passed a bad value', t => {
+	failsWith(t, () => {
+		assertions.notRegex(42, /foo/);
+	}, {
+		assertion: 'notRegex',
+		message: '`t.notRegex()` must be called with a string',
+		values: [{label: 'Called with:', formatted: /42/}]
+	});
+
+	failsWith(t, () => {
+		assertions.notRegex('42', {});
+	}, {
+		assertion: 'notRegex',
+		message: '`t.notRegex()` must be called with a regular expression',
+		values: [{label: 'Called with:', formatted: /Object/}]
+	});
+
+	t.end();
+});