1 files changed, 57 insertions, 3 deletions
diff --git a/cli/tests/unit/testing_test.ts b/cli/tests/unit/testing_test.ts
index 144246002..d4d25d12f 100644
--- a/cli/tests/unit/testing_test.ts
+++ b/cli/tests/unit/testing_test.ts
@@ -1,9 +1,63 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 import { assertRejects, assertThrows, unitTest } from "./test_util.ts";
 
-unitTest(function testFnOverloading() {
-  // just verifying that you can use this test definition syntax
-  Deno.test("test fn overloading", () => {});
+unitTest(function testWrongOverloads() {
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test("some name", { fn: () => {} }, () => {});
+    },
+    TypeError,
+    "Unexpected 'fn' field in options, test function is already provided as the third argument.",
+  );
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test("some name", { name: "some name2" }, () => {});
+    },
+    TypeError,
+    "Unexpected 'name' field in options, test name is already provided as the first argument.",
+  );
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test(() => {});
+    },
+    TypeError,
+    "The test function must have a name",
+  );
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test(function foo() {}, {});
+    },
+    TypeError,
+    "Unexpected second argument to Deno.test()",
+  );
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test({ fn: () => {} }, function foo() {});
+    },
+    TypeError,
+    "Unexpected 'fn' field in options, test function is already provided as the second argument.",
+  );
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test({});
+    },
+    TypeError,
+    "Expected 'fn' field in the first argument to be a test function.",
+  );
+  assertThrows(
+    () => {
+      // @ts-ignore Testing invalid overloads
+      Deno.test({ fn: "boo!" });
+    },
+    TypeError,
+    "Expected 'fn' field in the first argument to be a test function.",
+  );
 });
 
 unitTest(function nameOfTestCaseCantBeEmpty() {