Add resolved Python version output for activated environments

__tests__/utils/python-version.test.ts

@@ -0,0 +1,131 @@
+import * as path from "node:path";
+import type * as exec from "@actions/exec";
+import {
+  afterEach,
+  beforeEach,
+  describe,
+  expect,
+  it,
+  jest,
+} from "@jest/globals";
+import { createSetupInputs } from "../helpers/setup-inputs";
+
+const mockGetExecOutput = jest.fn<typeof exec.getExecOutput>();
+const mockDebug = jest.fn();
+const originalPlatform = process.platform;
+
+jest.unstable_mockModule("@actions/core", () => ({
+  debug: mockDebug,
+  isDebug: jest.fn(() => false),
+}));
+
+jest.unstable_mockModule("@actions/exec", () => ({
+  getExecOutput: mockGetExecOutput,
+}));
+
+const { getResolvedPythonVersion } = await import(
+  "../../src/utils/python-version"
+);
+
+beforeEach(() => {
+  mockGetExecOutput.mockReset();
+});
+
+afterEach(() => {
+  Object.defineProperty(process, "platform", { value: originalPlatform });
+});
+
+describe("getResolvedPythonVersion", () => {
+  it("does not query Python when environment activation is disabled", async () => {
+    const inputs = createSetupInputs({ pythonVersion: "3.15t" });
+
+    expect(await getResolvedPythonVersion(inputs)).toBe("");
+    expect(mockGetExecOutput).not.toHaveBeenCalled();
+  });
+
+  it.each([
+    ["3.13", "3.13.1"],
+    ["3.13.1t", "3.13.1"],
+    ["3.15t", "3.15.0rc1"],
+    ["pypy3.11", "3.11.11"],
+    ["", "3.12.9"],
+  ])(
+    "resolves %j to the interpreter's version %s",
+    async (request, version) => {
+      mockGetExecOutput.mockResolvedValue({
+        exitCode: 0,
+        stderr: "",
+        stdout: `${version}\r\n`,
+      });
+      const inputs = createSetupInputs({
+        activateEnvironment: true,
+        pythonVersion: request,
+      });
+
+      expect(await getResolvedPythonVersion(inputs)).toBe(version);
+      expect(inputs.pythonVersion).toBe(request);
+    },
+  );
+
+  it.each(["linux", "darwin", "win32"])(
+    "queries the custom venv directly on %s, including paths with spaces",
+    async (platform) => {
+      Object.defineProperty(process, "platform", { value: platform });
+      mockGetExecOutput.mockResolvedValue({
+        exitCode: 0,
+        stderr: "",
+        stdout: "3.13.1\n",
+      });
+      const inputs = createSetupInputs({
+        activateEnvironment: true,
+        venvPath: "/runner temp/custom venv",
+        workingDirectory: "/different/project",
+      });
+
+      await getResolvedPythonVersion(inputs);
+
+      const pythonPath =
+        platform === "win32"
+          ? path.join(inputs.venvPath, "Scripts", "python.exe")
+          : path.join(inputs.venvPath, "bin", "python");
+      expect(mockGetExecOutput).toHaveBeenCalledWith(
+        `"${pythonPath}"`,
+        ["-I", "-c", "import platform; print(platform.python_version())"],
+        { silent: true },
+      );
+    },
+  );
+
+  it("escapes quotes in the venv path for @actions/exec", async () => {
+    Object.defineProperty(process, "platform", { value: "linux" });
+    mockGetExecOutput.mockResolvedValue({
+      exitCode: 0,
+      stderr: "",
+      stdout: "3.13.1\n",
+    });
+    const inputs = createSetupInputs({
+      activateEnvironment: true,
+      venvPath: '/workspace/a "quoted" venv',
+    });
+
+    await getResolvedPythonVersion(inputs);
+
+    expect(mockGetExecOutput.mock.calls[0][0]).toContain('a \\"quoted\\" venv');
+  });
+
+  it.each([new Error("interpreter missing"), "interpreter failed"])(
+    "returns an empty output if the interpreter cannot be queried: %s",
+    async (error) => {
+      mockGetExecOutput.mockRejectedValue(error);
+
+      expect(
+        await getResolvedPythonVersion(
+          createSetupInputs({ activateEnvironment: true }),
+        ),
+      ).toBe("");
+      expect(mockDebug).toHaveBeenCalledWith(
+        expect.stringContaining(error instanceof Error ? error.message : error),
+      );
+    },
+  );
+});