diff --git a/cli/js/deno.ts b/cli/js/deno.ts
index 2c1d2a5b73fa0..ca323fc95051a 100644
--- a/cli/js/deno.ts
+++ b/cli/js/deno.ts
@@ -115,7 +115,13 @@ export { utimeSync, utime } from "./ops/fs/utime.ts";
 export { version } from "./version.ts";
 export { writeFileSync, writeFile, WriteFileOptions } from "./write_file.ts";
 export const args: string[] = [];
-export { test, runTests, TestEvent, ConsoleTestReporter } from "./testing.ts";
+export {
+  RunTestsOptions,
+  TestDefinition,
+  TestMessage,
+  runTests,
+  test,
+} from "./testing.ts";
 
 // These are internal Deno APIs.  We are marking them as internal so they do not
 // appear in the runtime type library.
diff --git a/cli/js/lib.deno.ns.d.ts b/cli/js/lib.deno.ns.d.ts
index ef1a820604969..f3e95c70deea9 100644
--- a/cli/js/lib.deno.ns.d.ts
+++ b/cli/js/lib.deno.ns.d.ts
@@ -12,10 +12,8 @@ declare namespace Deno {
    * See: https://no-color.org/ */
   export let noColor: boolean;
 
-  export type TestFunction = () => void | Promise<void>;
-
   export interface TestDefinition {
-    fn: TestFunction;
+    fn: () => void | Promise<void>;
     name: string;
     ignore?: boolean;
     disableOpSanitizer?: boolean;
@@ -70,7 +68,7 @@ declare namespace Deno {
    *          assertEquals(decoder.decode(data), "Hello world")
    *        });
    **/
-  export function test(fn: TestFunction): void;
+  export function test(fn: () => void | Promise<void>): void;
 
   /** Register a test which will be run when `deno test` is used on the command
    * line and the containing module looks like a test module, or explicitly
@@ -88,78 +86,37 @@ declare namespace Deno {
    *          assertEquals(decoder.decode(data), "Hello world")
    *        });
    * */
-  export function test(name: string, fn: TestFunction): void;
-
-  enum TestStatus {
-    Passed = "passed",
-    Failed = "failed",
-    Ignored = "ignored",
-  }
+  export function test(name: string, fn: () => void | Promise<void>): void;
 
-  interface TestResult {
-    name: string;
-    status: TestStatus;
-    duration?: number;
-    error?: Error;
-  }
-
-  interface TestStats {
-    filtered: number;
-    ignored: number;
-    measured: number;
-    passed: number;
-    failed: number;
-  }
-
-  export enum TestEvent {
-    Start = "start",
-    TestStart = "testStart",
-    TestEnd = "testEnd",
-    End = "end",
-  }
-
-  interface TestEventStart {
-    kind: TestEvent.Start;
-    tests: number;
-  }
-
-  interface TestEventTestStart {
-    kind: TestEvent.TestStart;
-    name: string;
-  }
-
-  interface TestEventTestEnd {
-    kind: TestEvent.TestEnd;
-    result: TestResult;
-  }
-
-  interface TestEventEnd {
-    kind: TestEvent.End;
-    stats: TestStats;
-    duration: number;
-    results: TestResult[];
-  }
-
-  interface TestReporter {
-    start(event: TestEventStart): Promise<void>;
-    testStart(msg: TestEventTestStart): Promise<void>;
-    testEnd(msg: TestEventTestEnd): Promise<void>;
-    end(event: TestEventEnd): Promise<void>;
-  }
-
-  export class ConsoleTestReporter implements TestReporter {
-    constructor();
-    start(event: TestEventStart): Promise<void>;
-    testStart(msg: TestEventTestStart): Promise<void>;
-    testEnd(msg: TestEventTestEnd): Promise<void>;
-    end(event: TestEventEnd): Promise<void>;
+  export interface TestMessage {
+    start?: {
+      tests: TestDefinition[];
+    };
+    testStart?: {
+      [P in keyof TestDefinition]: TestDefinition[P];
+    };
+    testEnd?: {
+      name: string;
+      status: "passed" | "failed" | "ignored";
+      duration: number;
+      error?: Error;
+    };
+    end?: {
+      filtered: number;
+      ignored: number;
+      measured: number;
+      passed: number;
+      failed: number;
+      duration: number;
+      results: Array<TestMessage["testEnd"] & {}>;
+    };
   }
 
   export interface RunTestsOptions {
     /** If `true`, Deno will exit with status code 1 if there was
      * test failure. Defaults to `true`. */
     exitOnFail?: boolean;
-    /** If `true`, Deno will exit upon first test failure Defaults to `false`. */
+    /** If `true`, Deno will exit upon first test failure. Defaults to `false`. */
     failFast?: boolean;
     /** String or RegExp used to filter test to run. Only test with names
      * matching provided `String` or `RegExp` will be run. */
@@ -169,8 +126,10 @@ declare namespace Deno {
     skip?: string | RegExp;
     /** Disable logging of the results. Defaults to `false`. */
     disableLog?: boolean;
-    /** Custom reporter class. If not provided uses console reporter. */
-    reporter?: TestReporter;
+    /** If true, report results to the console as is done for `deno test`. Defaults to `true`. */
+    reportToConsole?: boolean;
+    /** Called for each message received from the test run. */
+    onMessage?: (message: TestMessage) => void | Promise<void>;
   }
 
   /** Run any tests which have been registered via `Deno.test()`. Always resolves
@@ -193,11 +152,7 @@ declare namespace Deno {
    */
   export function runTests(
     opts?: RunTestsOptions
-  ): Promise<{
-    results: TestResult[];
-    stats: TestStats;
-    duration: number;
-  }>;
+  ): Promise<TestMessage["end"]> & {};
 
   /** Returns an array containing the 1, 5, and 15 minute load averages. The
    * load average is a measure of CPU and IO utilization of the last one, five,
diff --git a/cli/js/testing.ts b/cli/js/testing.ts
index 94a4cc7026bd7..5f1a62c63c66d 100644
--- a/cli/js/testing.ts
+++ b/cli/js/testing.ts
@@ -3,6 +3,7 @@ import { gray, green, italic, red, yellow } from "./colors.ts";
 import { exit } from "./ops/os.ts";
 import { Console, stringifyArgs } from "./web/console.ts";
 import { stdout } from "./files.ts";
+import { exposeForTest } from "./internals.ts";
 import { TextEncoder } from "./web/text_encoding.ts";
 import { metrics } from "./ops/runtime.ts";
 import { resources } from "./ops/resources.ts";
@@ -18,12 +19,12 @@ function formatDuration(time = 0): string {
   return gray(italic(timeStr));
 }
 
-// Wrap `TestFunction` in additional assertion that makes sure
+// Wrap test function in additional assertion that makes sure
 // the test case does not leak async "ops" - ie. number of async
 // completed ops after the test is the same as number of dispatched
 // ops. Note that "unref" ops are ignored since in nature that are
 // optional.
-function assertOps(fn: TestFunction): TestFunction {
+function assertOps(fn: () => void | Promise<void>): () => void | Promise<void> {
   return async function asyncOpSanitizer(): Promise<void> {
     const pre = metrics();
     await fn();
@@ -38,17 +39,19 @@ function assertOps(fn: TestFunction): TestFunction {
 Before:
   - dispatched: ${pre.opsDispatchedAsync}
   - completed: ${pre.opsCompletedAsync}
-After: 
+After:
   - dispatched: ${post.opsDispatchedAsync}
   - completed: ${post.opsCompletedAsync}`
     );
   };
 }
 
-// Wrap `TestFunction` in additional assertion that makes sure
+// Wrap test function in additional assertion that makes sure
 // the test case does not "leak" resources - ie. resource table after
 // the test has exactly the same contents as before the test.
-function assertResources(fn: TestFunction): TestFunction {
+function assertResources(
+  fn: () => void | Promise<void>
+): () => void | Promise<void> {
   return async function resourceSanitizer(): Promise<void> {
     const pre = resources();
     await fn();
@@ -63,10 +66,8 @@ After: ${postStr}`;
   };
 }
 
-export type TestFunction = () => void | Promise<void>;
-
 export interface TestDefinition {
-  fn: TestFunction;
+  fn: () => void | Promise<void>;
   name: string;
   ignore?: boolean;
   disableOpSanitizer?: boolean;
@@ -76,13 +77,13 @@ export interface TestDefinition {
 const TEST_REGISTRY: TestDefinition[] = [];
 
 export function test(t: TestDefinition): void;
-export function test(fn: TestFunction): void;
-export function test(name: string, fn: TestFunction): void;
+export function test(fn: () => void | Promise<void>): void;
+export function test(name: string, fn: () => void | Promise<void>): void;
 // Main test function provided by Deno, as you can see it merely
 // creates a new object with "name" and "fn" fields.
 export function test(
-  t: string | TestDefinition | TestFunction,
-  fn?: TestFunction
+  t: string | TestDefinition | (() => void | Promise<void>),
+  fn?: () => void | Promise<void>
 ): void {
   let testDef: TestDefinition;
 
@@ -93,7 +94,7 @@ export function test(
     if (!t) {
       throw new TypeError("The test name can't be empty");
     }
-    testDef = { fn: fn as TestFunction, name: t, ignore: false };
+    testDef = { fn: fn as () => void | Promise<void>, name: t, ignore: false };
   } else if (typeof t === "function") {
     if (!t.name) {
       throw new TypeError("The test function can't be anonymous");
@@ -120,70 +121,98 @@ export function test(
   TEST_REGISTRY.push(testDef);
 }
 
-interface TestStats {
-  filtered: number;
-  ignored: number;
-  measured: number;
-  passed: number;
-  failed: number;
-}
-
-export interface RunTestsOptions {
-  exitOnFail?: boolean;
-  failFast?: boolean;
-  only?: string | RegExp;
-  skip?: string | RegExp;
-  disableLog?: boolean;
-  reporter?: TestReporter;
+export interface TestMessage {
+  start?: {
+    tests: TestDefinition[];
+  };
+  // Must be extensible, avoiding `testStart?: TestDefinition;`.
+  testStart?: {
+    [P in keyof TestDefinition]: TestDefinition[P];
+  };
+  testEnd?: {
+    name: string;
+    status: "passed" | "failed" | "ignored";
+    duration: number;
+    error?: Error;
+  };
+  end?: {
+    filtered: number;
+    ignored: number;
+    measured: number;
+    passed: number;
+    failed: number;
+    duration: number;
+    results: Array<TestMessage["testEnd"] & {}>;
+  };
 }
 
-enum TestStatus {
-  Passed = "passed",
-  Failed = "failed",
-  Ignored = "ignored",
-}
+const encoder = new TextEncoder();
 
-interface TestResult {
-  name: string;
-  status: TestStatus;
-  duration: number;
-  error?: Error;
-}
+function log(msg: string, noNewLine = false): void {
+  if (!noNewLine) {
+    msg += "\n";
+  }
 
-export enum TestEvent {
-  Start = "start",
-  TestStart = "testStart",
-  TestEnd = "testEnd",
-  End = "end",
+  // Using `stdout` here because it doesn't force new lines
+  // compared to `console.log`; `core.print` on the other hand
+  // is line-buffered and doesn't output message without newline
+  stdout.writeSync(encoder.encode(msg));
 }
 
-interface TestEventStart {
-  kind: TestEvent.Start;
-  tests: number;
-}
+function reportToConsole(message: TestMessage): void {
+  if (message.start != null) {
+    log(`running ${message.start.tests.length} tests`);
+  } else if (message.testStart != null) {
+    const { name } = message.testStart;
+
+    log(`test ${name} ... `, true);
+    return;
+  } else if (message.testEnd != null) {
+    switch (message.testEnd.status) {
+      case "passed":
+        log(`${GREEN_OK} ${formatDuration(message.testEnd.duration)}`);
+        break;
+      case "failed":
+        log(`${RED_FAILED} ${formatDuration(message.testEnd.duration)}`);
+        break;
+      case "ignored":
+        log(`${YELLOW_IGNORED} ${formatDuration(message.testEnd.duration)}`);
+        break;
+    }
+  } else if (message.end != null) {
+    const failures = message.end.results.filter((m) => m.error != null);
+    if (failures.length > 0) {
+      log(`\nfailures:\n`);
+
+      for (const { name, error } of failures) {
+        log(name);
+        log(stringifyArgs([error!]));
+        log("");
+      }
 
-interface TestEventTestStart {
-  kind: TestEvent.TestStart;
-  name: string;
-}
+      log(`failures:\n`);
 
-interface TestEventTestEnd {
-  kind: TestEvent.TestEnd;
-  result: TestResult;
+      for (const { name } of failures) {
+        log(`\t${name}`);
+      }
+    }
+    log(
+      `\ntest result: ${message.end.failed ? RED_FAILED : GREEN_OK}. ` +
+        `${message.end.passed} passed; ${message.end.failed} failed; ` +
+        `${message.end.ignored} ignored; ${message.end.measured} measured; ` +
+        `${message.end.filtered} filtered out ` +
+        `${formatDuration(message.end.duration)}\n`
+    );
+  }
 }
 
-interface TestEventEnd {
-  kind: TestEvent.End;
-  stats: TestStats;
-  duration: number;
-  results: TestResult[];
-}
+exposeForTest("reportToConsole", reportToConsole);
 
 // TODO: already implements AsyncGenerator<RunTestsMessage>, but add as "implements to class"
-// TODO: implements PromiseLike<TestsResult>
+// TODO: implements PromiseLike<RunTestsEndResult>
 class TestApi {
   readonly testsToRun: TestDefinition[];
-  readonly stats: TestStats = {
+  readonly stats = {
     filtered: 0,
     ignored: 0,
     measured: 0,
@@ -200,51 +229,43 @@ class TestApi {
     this.stats.filtered = tests.length - this.testsToRun.length;
   }
 
-  async *[Symbol.asyncIterator](): AsyncIterator<
-    TestEventStart | TestEventTestStart | TestEventTestEnd | TestEventEnd
-  > {
-    yield {
-      kind: TestEvent.Start,
-      tests: this.testsToRun.length,
-    };
+  async *[Symbol.asyncIterator](): AsyncIterator<TestMessage> {
+    yield { start: { tests: this.testsToRun } };
 
-    const results: TestResult[] = [];
+    const results: Array<TestMessage["testEnd"] & {}> = [];
     const suiteStart = +new Date();
-    for (const { name, fn, ignore } of this.testsToRun) {
-      const result: Partial<TestResult> = { name, duration: 0 };
-      yield { kind: TestEvent.TestStart, name };
-      if (ignore) {
-        result.status = TestStatus.Ignored;
+    for (const test of this.testsToRun) {
+      const endMessage: Partial<TestMessage["testEnd"] & {}> = {
+        name: test.name,
+        duration: 0,
+      };
+      yield { testStart: { ...test } };
+      if (test.ignore) {
+        endMessage.status = "ignored";
         this.stats.ignored++;
       } else {
         const start = +new Date();
         try {
-          await fn();
-          result.status = TestStatus.Passed;
+          await test.fn();
+          endMessage.status = "passed";
           this.stats.passed++;
         } catch (err) {
-          result.status = TestStatus.Failed;
-          result.error = err;
+          endMessage.status = "failed";
+          endMessage.error = err;
           this.stats.failed++;
-        } finally {
-          result.duration = +new Date() - start;
         }
+        endMessage.duration = +new Date() - start;
       }
-      yield { kind: TestEvent.TestEnd, result: result as TestResult };
-      results.push(result as TestResult);
-      if (this.failFast && result.error != null) {
+      results.push(endMessage as TestMessage["testEnd"] & {});
+      yield { testEnd: endMessage as TestMessage["testEnd"] };
+      if (this.failFast && endMessage.error != null) {
         break;
       }
     }
 
     const duration = +new Date() - suiteStart;
 
-    yield {
-      kind: TestEvent.End,
-      stats: this.stats,
-      results,
-      duration,
-    };
+    yield { end: { ...this.stats, duration, results } };
   }
 }
 
@@ -275,95 +296,14 @@ function createFilterFn(
   };
 }
 
-interface TestReporter {
-  start(msg: TestEventStart): Promise<void>;
-  testStart(msg: TestEventTestStart): Promise<void>;
-  testEnd(msg: TestEventTestEnd): Promise<void>;
-  end(msg: TestEventEnd): Promise<void>;
-}
-
-export class ConsoleTestReporter implements TestReporter {
-  start(event: TestEventStart): Promise<void> {
-    ConsoleTestReporter.log(`running ${event.tests} tests`);
-    return Promise.resolve();
-  }
-
-  testStart(event: TestEventTestStart): Promise<void> {
-    const { name } = event;
-
-    ConsoleTestReporter.log(`test ${name} ... `, true);
-    return Promise.resolve();
-  }
-
-  testEnd(event: TestEventTestEnd): Promise<void> {
-    const { result } = event;
-
-    switch (result.status) {
-      case TestStatus.Passed:
-        ConsoleTestReporter.log(
-          `${GREEN_OK} ${formatDuration(result.duration)}`
-        );
-        break;
-      case TestStatus.Failed:
-        ConsoleTestReporter.log(
-          `${RED_FAILED} ${formatDuration(result.duration)}`
-        );
-        break;
-      case TestStatus.Ignored:
-        ConsoleTestReporter.log(
-          `${YELLOW_IGNORED} ${formatDuration(result.duration)}`
-        );
-        break;
-    }
-
-    return Promise.resolve();
-  }
-
-  end(event: TestEventEnd): Promise<void> {
-    const { stats, duration, results } = event;
-    // Attempting to match the output of Rust's test runner.
-    const failedTests = results.filter((r) => r.error);
-
-    if (failedTests.length > 0) {
-      ConsoleTestReporter.log(`\nfailures:\n`);
-
-      for (const result of failedTests) {
-        ConsoleTestReporter.log(`${result.name}`);
-        ConsoleTestReporter.log(`${stringifyArgs([result.error!])}`);
-        ConsoleTestReporter.log("");
-      }
-
-      ConsoleTestReporter.log(`failures:\n`);
-
-      for (const result of failedTests) {
-        ConsoleTestReporter.log(`\t${result.name}`);
-      }
-    }
-
-    ConsoleTestReporter.log(
-      `\ntest result: ${stats.failed ? RED_FAILED : GREEN_OK}. ` +
-        `${stats.passed} passed; ${stats.failed} failed; ` +
-        `${stats.ignored} ignored; ${stats.measured} measured; ` +
-        `${stats.filtered} filtered out ` +
-        `${formatDuration(duration)}\n`
-    );
-
-    return Promise.resolve();
-  }
-
-  static encoder = new TextEncoder();
-
-  static log(msg: string, noNewLine = false): Promise<void> {
-    if (!noNewLine) {
-      msg += "\n";
-    }
-
-    // Using `stdout` here because it doesn't force new lines
-    // compared to `console.log`; `core.print` on the other hand
-    // is line-buffered and doesn't output message without newline
-    stdout.writeSync(ConsoleTestReporter.encoder.encode(msg));
-    return Promise.resolve();
-  }
+export interface RunTestsOptions {
+  exitOnFail?: boolean;
+  failFast?: boolean;
+  only?: string | RegExp;
+  skip?: string | RegExp;
+  disableLog?: boolean;
+  reportToConsole?: boolean;
+  onMessage?: (message: TestMessage) => void | Promise<void>;
 }
 
 export async function runTests({
@@ -372,19 +312,12 @@ export async function runTests({
   only = undefined,
   skip = undefined,
   disableLog = false,
-  reporter = undefined,
-}: RunTestsOptions = {}): Promise<{
-  results: TestResult[];
-  stats: TestStats;
-  duration: number;
-}> {
+  reportToConsole: reportToConsole_ = true,
+  onMessage = undefined,
+}: RunTestsOptions = {}): Promise<TestMessage["end"] & {}> {
   const filterFn = createFilterFn(only, skip);
   const testApi = new TestApi(TEST_REGISTRY, filterFn, failFast);
 
-  if (!reporter) {
-    reporter = new ConsoleTestReporter();
-  }
-
   // @ts-ignore
   const originalConsole = globalThis.console;
 
@@ -393,24 +326,17 @@ export async function runTests({
     globalThis.console = disabledConsole;
   }
 
-  let endMsg: TestEventEnd;
-
-  for await (const testMsg of testApi) {
-    switch (testMsg.kind) {
-      case TestEvent.Start:
-        await reporter.start(testMsg);
-        continue;
-      case TestEvent.TestStart:
-        await reporter.testStart(testMsg);
-        continue;
-      case TestEvent.TestEnd:
-        await reporter.testEnd(testMsg);
-        continue;
-      case TestEvent.End:
-        endMsg = testMsg;
-        delete endMsg!.kind;
-        await reporter.end(testMsg);
-        continue;
+  let endMsg: TestMessage["end"];
+
+  for await (const message of testApi) {
+    if (onMessage != null) {
+      await onMessage(message);
+    }
+    if (reportToConsole_) {
+      reportToConsole(message);
+    }
+    if (message.end != null) {
+      endMsg = message.end;
     }
   }
 
@@ -419,7 +345,7 @@ export async function runTests({
     globalThis.console = originalConsole;
   }
 
-  if (endMsg!.stats.failed > 0 && exitOnFail) {
+  if (endMsg!.failed > 0 && exitOnFail) {
     exit(1);
   }
 
diff --git a/cli/js/tests/format_error_test.ts b/cli/js/tests/format_error_test.ts
index 42c16b0c03745..0cb963ae69311 100644
--- a/cli/js/tests/format_error_test.ts
+++ b/cli/js/tests/format_error_test.ts
@@ -31,7 +31,3 @@ unitTest(function formatDiagnosticError() {
   }
   assert(thrown);
 });
-
-if (import.meta.main) {
-  Deno.runTests();
-}
diff --git a/cli/js/tests/test_util.ts b/cli/js/tests/test_util.ts
index da2e917f8b5d2..a3b4b6ce46cd1 100644
--- a/cli/js/tests/test_util.ts
+++ b/cli/js/tests/test_util.ts
@@ -132,19 +132,21 @@ interface UnitTestDefinition extends Deno.TestDefinition {
   perms: Permissions;
 }
 
+type TestFunction = () => void | Promise<void>;
+
 export const REGISTERED_UNIT_TESTS: UnitTestDefinition[] = [];
 
-export function unitTest(fn: Deno.TestFunction): void;
-export function unitTest(options: UnitTestOptions, fn: Deno.TestFunction): void;
+export function unitTest(fn: TestFunction): void;
+export function unitTest(options: UnitTestOptions, fn: TestFunction): void;
 export function unitTest(
-  optionsOrFn: UnitTestOptions | Deno.TestFunction,
-  maybeFn?: Deno.TestFunction
+  optionsOrFn: UnitTestOptions | TestFunction,
+  maybeFn?: TestFunction
 ): void {
   assert(optionsOrFn, "At least one argument is required");
 
   let options: UnitTestOptions;
   let name: string;
-  let fn: Deno.TestFunction;
+  let fn: TestFunction;
 
   if (typeof optionsOrFn === "function") {
     options = {};
@@ -196,44 +198,38 @@ export function createResolvable<T>(): Resolvable<T> {
 
 const encoder = new TextEncoder();
 
-export class SocketReporter implements Deno.TestReporter {
-  #conn: Deno.Conn;
-
-  constructor(conn: Deno.Conn) {
-    this.#conn = conn;
-  }
-
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  async write(msg: any): Promise<void> {
-    const encodedMsg = encoder.encode(JSON.stringify(msg) + "\n");
-    await Deno.writeAll(this.#conn, encodedMsg);
-  }
-
-  async start(msg: Deno.TestEventStart): Promise<void> {
-    await this.write(msg);
-  }
-
-  async testStart(msg: Deno.TestEventTestStart): Promise<void> {
-    await this.write(msg);
-  }
-
-  async testEnd(msg: Deno.TestEventTestEnd): Promise<void> {
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    const serializedMsg: any = { ...msg };
-
-    // Error is a JS object, so we need to turn it into string to
-    // send over socket.
-    if (serializedMsg.result.error) {
-      serializedMsg.result.error = String(serializedMsg.result.error.stack);
-    }
-
-    await this.write(serializedMsg);
-  }
+// Replace functions with null, errors with their stack strings, and JSONify.
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+function serializeTestMessage(message: Deno.TestMessage): string {
+  return JSON.stringify({
+    start: message.start && {
+      ...message.start,
+      tests: message.start.tests.map((test) => ({ ...test, fn: null })),
+    },
+    testStart: message.testStart && { ...message.testStart, fn: null },
+    testEnd: message.testEnd && {
+      ...message.testEnd,
+      error: String(message.testEnd.error?.stack),
+    },
+    end: message.end && {
+      ...message.end,
+      results: message.end.results.map((result) => ({
+        ...result,
+        error: result.error?.stack,
+      })),
+    },
+  });
+}
 
-  async end(msg: Deno.TestEventEnd): Promise<void> {
-    const encodedMsg = encoder.encode(JSON.stringify(msg));
-    await Deno.writeAll(this.#conn, encodedMsg);
-    this.#conn.closeWrite();
+export async function reportToConn(
+  conn: Deno.Conn,
+  message: Deno.TestMessage
+): Promise<void> {
+  const line = serializeTestMessage(message);
+  const encodedMsg = encoder.encode(line + (message.end == null ? "\n" : ""));
+  await Deno.writeAll(conn, encodedMsg);
+  if (message.end != null) {
+    conn.closeWrite();
   }
 }
 
diff --git a/cli/js/tests/unit_test_runner.ts b/cli/js/tests/unit_test_runner.ts
index 8d3eaa4f5ca71..0232bb43774c0 100755
--- a/cli/js/tests/unit_test_runner.ts
+++ b/cli/js/tests/unit_test_runner.ts
@@ -6,18 +6,20 @@ import {
   permissionCombinations,
   Permissions,
   registerUnitTests,
-  SocketReporter,
   fmtPerms,
   parseArgs,
+  reportToConn,
 } from "./test_util.ts";
 
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const reportToConsole = (Deno as any)[Deno.symbols.internal]
+  .reportToConsole as (message: Deno.TestMessage) => void;
+
 interface PermissionSetTestResult {
   perms: Permissions;
   passed: boolean;
-  stats: Deno.TestStats;
+  endMessage: Deno.TestMessage["end"];
   permsStr: string;
-  duration: number;
-  results: Deno.TestResult[];
 }
 
 const PERMISSIONS: Deno.PermissionName[] = [
@@ -59,17 +61,16 @@ async function workerRunnerMain(
   }
   // Setup reporter
   const conn = await Deno.connect(addr);
-  const socketReporter = new SocketReporter(conn);
   // Drop current process permissions to requested set
   await dropWorkerPermissions(perms);
   // Register unit tests that match process permissions
   await registerUnitTests();
   // Execute tests
   await Deno.runTests({
-    failFast: false,
     exitOnFail: false,
-    reporter: socketReporter,
     only: filter,
+    reportToConsole: false,
+    onMessage: reportToConn.bind(null, conn),
   });
 }
 
@@ -117,7 +118,6 @@ async function runTestsForPermissionSet(
   listener: Deno.Listener,
   addrStr: string,
   verbose: boolean,
-  reporter: Deno.ConsoleTestReporter,
   perms: Permissions,
   filter?: string
 ): Promise<PermissionSetTestResult> {
@@ -128,22 +128,16 @@ async function runTestsForPermissionSet(
   const conn = await listener.accept();
 
   let expectedPassedTests;
-  let endEvent;
+  let endMessage: Deno.TestMessage["end"];
 
   try {
     for await (const line of readLines(conn)) {
-      const msg = JSON.parse(line);
-
-      if (msg.kind === Deno.TestEvent.Start) {
-        expectedPassedTests = msg.tests;
-        await reporter.start(msg);
-      } else if (msg.kind === Deno.TestEvent.TestStart) {
-        await reporter.testStart(msg);
-      } else if (msg.kind === Deno.TestEvent.TestEnd) {
-        await reporter.testEnd(msg);
-      } else {
-        endEvent = msg;
-        await reporter.end(msg);
+      const message = JSON.parse(line) as Deno.TestMessage;
+      reportToConsole(message);
+      if (message.start != null) {
+        expectedPassedTests = message.start.tests.length;
+      } else if (message.end != null) {
+        endMessage = message.end;
       }
     }
   } finally {
@@ -151,11 +145,11 @@ async function runTestsForPermissionSet(
     conn.close();
   }
 
-  if (expectedPassedTests === undefined) {
+  if (expectedPassedTests == null) {
     throw new Error("Worker runner didn't report start");
   }
 
-  if (endEvent === undefined) {
+  if (endMessage == null) {
     throw new Error("Worker runner didn't report end");
   }
 
@@ -168,16 +162,13 @@ async function runTestsForPermissionSet(
 
   workerProcess.close();
 
-  const passed =
-    expectedPassedTests === endEvent.stats.passed + endEvent.stats.ignored;
+  const passed = expectedPassedTests === endMessage.passed + endMessage.ignored;
 
   return {
     perms,
     passed,
     permsStr: permsFmt,
-    duration: endEvent.duration,
-    stats: endEvent.stats,
-    results: endEvent.results,
+    endMessage,
   };
 }
 
@@ -195,7 +186,6 @@ async function masterRunnerMain(
   }
 
   const testResults = new Set<PermissionSetTestResult>();
-  const consoleReporter = new Deno.ConsoleTestReporter();
   const addr = { hostname: "127.0.0.1", port: 4510 };
   const addrStr = `${addr.hostname}:${addr.port}`;
   const listener = Deno.listen(addr);
@@ -205,7 +195,6 @@ async function masterRunnerMain(
       listener,
       addrStr,
       verbose,
-      consoleReporter,
       perms,
       filter
     );
@@ -217,14 +206,9 @@ async function masterRunnerMain(
   let testsPassed = true;
 
   for (const testResult of testResults) {
-    const { permsStr, stats, duration, results } = testResult;
+    const { permsStr, endMessage } = testResult;
     console.log(`Summary for ${permsStr}`);
-    await consoleReporter.end({
-      kind: Deno.TestEvent.End,
-      stats,
-      duration,
-      results,
-    });
+    reportToConsole({ end: endMessage });
     testsPassed = testsPassed && testResult.passed;
   }
 
@@ -312,11 +296,7 @@ async function main(): Promise<void> {
 
   // Running tests matching current process permissions
   await registerUnitTests();
-  await Deno.runTests({
-    failFast: false,
-    exitOnFail: true,
-    only: filter,
-  });
+  await Deno.runTests({ only: filter });
 }
 
 main();
diff --git a/cli/js/tests/url_test.ts b/cli/js/tests/url_test.ts
index e1b2d47bdc9f8..e4d497ffb4c2e 100644
--- a/cli/js/tests/url_test.ts
+++ b/cli/js/tests/url_test.ts
@@ -212,7 +212,3 @@ unitTest(function createBadUrl(): void {
     new URL("0.0.0.0:8080");
   });
 });
-
-if (import.meta.main) {
-  Deno.runTests();
-}
diff --git a/std/fs/walk_test.ts b/std/fs/walk_test.ts
index 96bfcae67571e..57d3cf8eab5f6 100644
--- a/std/fs/walk_test.ts
+++ b/std/fs/walk_test.ts
@@ -7,7 +7,7 @@ const isWindows = Deno.build.os == "win";
 
 export function testWalk(
   setup: (arg0: string) => void | Promise<void>,
-  t: Deno.TestFunction,
+  t: () => void | Promise<void>,
   ignore = false
 ): void {
   const name = t.name;
diff --git a/std/testing/README.md b/std/testing/README.md
index c7c614103edbd..711aa02575d47 100644
--- a/std/testing/README.md
+++ b/std/testing/README.md
@@ -46,8 +46,6 @@ Deno.test({
     assertEquals({ hello: "world" }, { hello: "world" });
   },
 });
-
-await Deno.runTests();
 ```
 
 Short syntax (named function instead of object):