test(action): Import types statically

Prefer static type imports (using the import keyword) to dynamic type
imports (using the import() function). Unlike regular static imports,
static type imports do not interfere with mocking as they compile out,
so there is no need to delay them until after our mocks are set up.
Introduce types/aliases.ts to export convenient names for the shapes of
our production modules that we import in our tests. We use these types
to ensure that our mocks accurately reflect the shapes of their
production counterparts.

src/docker.test.ts

@@ -5,12 +5,16 @@ import { boolean, string, uniqueArray } from "fast-check";
 import type { InputOptions } from "@actions/core";
 import type { FunctionLike } from "jest-mock";
 
+import type { Util } from "../types/aliases.js";
+import type { execBashCommand } from "./util.js";
+
 jest.mock("@actions/cache");
 jest.mock("@actions/core");
 
-jest.unstable_mockModule("./util.js", (): typeof import("./util.js") => ({
-  execBashCommand: jest.fn<typeof import("./util.js").execBashCommand>(),
-}));
+jest.unstable_mockModule(
+  "./util.js",
+  (): Util => ({ execBashCommand: jest.fn<typeof execBashCommand>() })
+);
 
 const cache = jest.mocked(await import("@actions/cache"));
 const core = jest.mocked(await import("@actions/core"));

src/integration.test.ts

@@ -4,13 +4,13 @@ import { string } from "fast-check";
 
 import { consoleOutput } from "./arbitraries/util.js";
 
-import type { ExecOptions } from "node:child_process";
+import type { exec, ExecOptions } from "node:child_process";
 import type { InputOptions } from "@actions/core";
 
 import type { ConsoleOutput } from "./util.js";
 
 jest.unstable_mockModule("node:child_process", () => ({
-  exec: jest.fn<typeof import("node:child_process").exec>(),
+  exec: jest.fn<typeof exec>(),
 }));
 jest.mock("@actions/cache");
 jest.mock("@actions/core");
@@ -64,7 +64,7 @@ describe("Integration Test", (): void => {
   });
 
   const mockExec = (listStderr: string, otherOutput: ConsoleOutput): void => {
-    child_process.exec.mockImplementation(<typeof child_process.exec>((
+    child_process.exec.mockImplementation(<typeof exec>((
       command: string,
       _options: any,
       callback: any

src/main.test.ts

@@ -1,9 +1,12 @@
 import { jest } from "@jest/globals";
 
+import type { loadDockerImages } from "./docker.js";
+import type { Docker } from "../types/aliases.js";
+
 jest.unstable_mockModule(
   "./docker.js",
-  (): Partial<typeof import("./docker.js")> => ({
-    loadDockerImages: jest.fn<typeof import("./docker.js").loadDockerImages>(),
+  (): Partial<Docker> => ({
+    loadDockerImages: jest.fn<typeof loadDockerImages>(),
   })
 );
 

src/post.test.ts

@@ -1,9 +1,12 @@
 import { jest } from "@jest/globals";
 
+import type { saveDockerImages } from "./docker.js";
+import type { Docker } from "../types/aliases.js";
+
 jest.unstable_mockModule(
   "./docker.js",
-  (): Partial<typeof import("./docker.js")> => ({
-    saveDockerImages: jest.fn<typeof import("./docker.js").saveDockerImages>(),
+  (): Partial<Docker> => ({
+    saveDockerImages: jest.fn<typeof saveDockerImages>(),
   })
 );
 

src/util.test.ts

@@ -4,10 +4,12 @@ import { string } from "fast-check";
 
 import { consoleOutput, platform } from "./arbitraries/util.js";
 
+import type { exec } from "node:child_process";
+
 import type { ConsoleOutput } from "./util.js";
 
 jest.unstable_mockModule("node:child_process", () => ({
-  exec: jest.fn<typeof import("node:child_process").exec>(),
+  exec: jest.fn<typeof exec>(),
 }));
 
 jest.mock("@actions/core");
@@ -24,7 +26,7 @@ describe("Util", (): void => {
       platform: NodeJS.Platform,
       output: ConsoleOutput
     ): Promise<string> => {
-      child_process.exec.mockImplementationOnce(<typeof child_process.exec>((
+      child_process.exec.mockImplementationOnce(<typeof exec>((
         _command: any,
         _options: any,
         callback: any

types/aliases.ts

@@ -0,0 +1,5 @@
+import type * as docker from "../src/docker.js";
+import type * as util from "../src/util.js";
+
+export type Docker = typeof docker;
+export type Util = typeof util;