fix: invalid chai property error when chai is added globally

Author: webpapaya

lib/assertThat.js

@@ -41,7 +41,7 @@ const assertThat = (...args) => {
 	} else {
 		if (global && global.expect) {
 			const expectation = global.expect();
-			if (expectation && expectation.nothing) {
+			if (expectation && 'nothing' in expectation) {
 				expectation.nothing();
 			}
 		}

test/node/assertThatSpec.js

@@ -114,4 +114,18 @@ describe('assertThat', () => {
 
 		assert.equal(expectNothingWasCalled, true);
 	});
+
+	it('should not throw when nothing is not available on expect (fix "Invalid Chai property" in vitest)', () => {
+		const chaiFake = {irrelevant: 'property'};
+
+		global.expect = () => new Proxy(chaiFake, {
+			get(target, property) {
+				if (!Object.keys(target).includes(property)) {
+					throw Error(`Invalid Chai property: ${property}`);
+				}
+			}
+		});
+
+		__.assertThat(true, __.is(__.equalTo(true)));
+	});
 });