feat(test): Add "name", "origin" and "parent" to "Deno.TestContext" (#14007)

This commit adds following fields to "Deno.TestContext" interface:
- name
- origin
- parent

These are prerequisites for supporting snapshot functionality in
"std/testing".

3 files changed, 70 insertions, 2 deletions

diff --git a/cli/dts/lib.deno.ns.d.ts b/cli/dts/lib.deno.ns.d.ts
index d55ac231e..485b3d490 100644
--- a/cli/dts/lib.deno.ns.d.ts
+++ b/cli/dts/lib.deno.ns.d.ts
@@ -250,6 +250,19 @@ declare namespace Deno {
   }
 
   export interface TestContext {
+    /**
+     * The current test name.
+     */
+    name: string;
+    /**
+     * File Uri of the current test code.
+     */
+    origin: string;
+    /**
+     * Parent test context.
+     */
+    parent?: TestContext;
+
     /** Run a sub step of the parent test or step. Returns a promise
      * that resolves to a boolean signifying if the step completed successfully.
      * The returned promise never rejects unless the arguments are invalid.
@@ -270,6 +283,9 @@ declare namespace Deno {
 
   export interface TestStepDefinition {
     fn: (t: TestContext) => void | Promise<void>;
+    /**
+     * The current test name.
+     */
     name: string;
     ignore?: boolean;
     /** Check that the number of async completed ops after the test step is the same
@@ -287,6 +303,9 @@ declare namespace Deno {
 
   export interface TestDefinition {
     fn: (t: TestContext) => void | Promise<void>;
+    /**
+     * The current test name.
+     */
     name: string;
     ignore?: boolean;
     /** If at least one test has `only` set to true, only run tests that have
diff --git a/cli/tests/unit/testing_test.ts b/cli/tests/unit/testing_test.ts
index 87b862a7d..90575aeb2 100644
--- a/cli/tests/unit/testing_test.ts
+++ b/cli/tests/unit/testing_test.ts
@@ -1,5 +1,5 @@
 // Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
-import { assertRejects, assertThrows } from "./test_util.ts";
+import { assertEquals, assertRejects, assertThrows } from "./test_util.ts";
 
 Deno.test(function testWrongOverloads() {
   assertThrows(
@@ -117,3 +117,33 @@ Deno.test(async function invalidStepArguments(t) {
     "Expected a test definition or name and function.",
   );
 });
+
+Deno.test(async function nameOnTextContext(t1) {
+  await assertEquals(t1.name, "nameOnTextContext");
+  await t1.step("step", async (t2) => {
+    await assertEquals(t2.name, "step");
+    await t2.step("nested step", async (t3) => {
+      await assertEquals(t3.name, "nested step");
+    });
+  });
+});
+
+Deno.test(async function originOnTextContext(t1) {
+  await assertEquals(t1.origin, Deno.mainModule);
+  await t1.step("step", async (t2) => {
+    await assertEquals(t2.origin, Deno.mainModule);
+    await t2.step("nested step", async (t3) => {
+      await assertEquals(t3.origin, Deno.mainModule);
+    });
+  });
+});
+
+Deno.test(async function parentOnTextContext(t1) {
+  await assertEquals(t1.parent, undefined);
+  await t1.step("step", async (t2) => {
+    await assertEquals(t1, t2.parent);
+    await t2.step("nested step", async (t3) => {
+      await assertEquals(t2, t3.parent);
+    });
+  });
+});
diff --git a/runtime/js/40_testing.js b/runtime/js/40_testing.js
index abbef2ae4..0b75daa24 100644
--- a/runtime/js/40_testing.js
+++ b/runtime/js/40_testing.js
@@ -792,6 +792,7 @@
     const step = new TestStep({
       name: test.name,
       parent: undefined,
+      parentContext: undefined,
       rootTestDescription: description,
       sanitizeOps: test.sanitizeOps,
       sanitizeResources: test.sanitizeResources,
@@ -1064,8 +1065,9 @@
    * }} TestStepDefinition
    *
    * @typedef {{
-   *   name: string;
+   *   name: string,
    *   parent: TestStep | undefined,
+   *   parentContext: TestContext | undefined,
    *   rootTestDescription: { origin: string; name: string };
    *   sanitizeOps: boolean,
    *   sanitizeResources: boolean,
@@ -1099,6 +1101,10 @@
       return this.#params.parent;
     }
 
+    get parentContext() {
+      return this.#params.parentContext;
+    }
+
     get rootTestDescription() {
       return this.#params.rootTestDescription;
     }
@@ -1269,6 +1275,18 @@
     return {
       [SymbolToStringTag]: "TestContext",
       /**
+       * The current test name.
+       */
+      name: parentStep.name,
+      /**
+       * Parent test context.
+       */
+      parent: parentStep.parentContext ?? undefined,
+      /**
+       * File Uri of the test code.
+       */
+      origin: parentStep.rootTestDescription.origin,
+      /**
        * @param nameOrTestDefinition {string | TestStepDefinition}
        * @param fn {(t: TestContext) => void | Promise<void>}
        */
@@ -1284,6 +1302,7 @@
         const subStep = new TestStep({
           name: definition.name,
           parent: parentStep,
+          parentContext: this,
           rootTestDescription: parentStep.rootTestDescription,
           sanitizeOps: getOrDefault(
             definition.sanitizeOps,