fix(cli): not to show 1 test when no tests are in the file (#7205)

This is to fix an issue that caused `wing test` against an empty `some_file_name.w` file shows `Tests 1 passed (1)`.

See the issue #5852 for details.

Solution:
Instead of adding a dummy pass message, the function now returns early with a predefined message when there's no test case to avoid confusion later.

And I don't think it would need full E2E tests?

I am still exploring how to add test for this new test system behavior. Will mark the PR as ready after adding/updating test for it.

## Checklist

- [x] Title matches [Winglang's style guide](https://www.winglang.io/contributing/start-here/pull_requests#how-are-pull-request-titles-formatted)
- [x] Description explains motivation and solution
- [x] Tests added (always)
- [x] Added `pr/e2e-full` label if this feature requires end-to-end testing

*By submitting this pull request, I confirm that my contribution is made under the terms of the [Wing Cloud Contribution License](https://github.com/winglang/wing/blob/main/CONTRIBUTION_LICENSE.md)*.

Resolves #5852

packages/winglang/src/commands/test/__snapshots__/test.test.ts.snap

@@ -1,5 +1,7 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
+exports[`printing test reports > results for files with no tests 1`] = `"pass ─ hello.w (no tests)"`;
+
 exports[`printing test reports > verbose traces are not shown if debug mode is disabled 1`] = `
 "fail ┌ hello.w » root/env0/test:test
      │ sleeping for 500 ms

packages/winglang/src/commands/test/test.test.ts

@@ -5,7 +5,7 @@ import { join } from "path";
 import { BuiltinPlatform } from "@winglang/compiler";
 import { LogLevel, TestResult, TraceType } from "@winglang/sdk/lib/std";
 import chalk from "chalk";
-import { describe, test, expect, beforeEach, afterEach, vi, SpyInstance } from "vitest";
+import { describe, test, expect, beforeEach, afterEach, vi, MockInstance } from "vitest";
 import { filterTests, renderTestReport, collectTestFiles, test as wingTest } from ".";
 import * as resultsFn from "./results";
 import { SnapshotMode } from "./snapshots";
@@ -45,10 +45,21 @@ describe("printing test reports", () => {
     expect(testReport).toMatchSnapshot();
     expect(testReport).toContain("Push (message=cool)");
   });
+
+  test("results for files with no tests", async () => {
+    let inputResults: TestResult[] = [];
+    const testReport = await renderTestReport("hello.w", inputResults);
+
+    expect(testReport).toMatchSnapshot();
+    expect(testReport).toContain("(no tests)");
+
+    // verify that the the no dummy test results were added
+    expect(inputResults).toHaveLength(0);
+  });
 });
 
 describe("wing test (custom platform)", () => {
-  let logSpy: SpyInstance;
+  let logSpy: MockInstance;
 
   beforeEach(() => {
     chalk.level = 0;
@@ -208,7 +219,7 @@ describe("collectTestFiles", () => {
 });
 
 describe("output-file option", () => {
-  let writeResultsSpy: SpyInstance;
+  let writeResultsSpy: MockInstance;
 
   beforeEach(() => {
     chalk.level = 0;
@@ -304,7 +315,7 @@ describe("test-filter option", () => {
 });
 
 describe("retry and parallel options", () => {
-  let logSpy: SpyInstance;
+  let logSpy: MockInstance;
 
   beforeEach(() => {
     chalk.level = 0;

packages/winglang/src/commands/test/test.ts

@@ -262,14 +262,10 @@ export async function renderTestReport(
     0
   );
 
-  // if there are no inflight tests, add a dummy "pass" result
+  // return early if there are no tests, return a pass output
   // to indicate that compilation and preflight checks passed
   if (results.length === 0) {
-    results.push({
-      pass: true,
-      path: "",
-      traces: [],
-    });
+    return `${chalk.green("pass")} ─ ${basename(entrypoint)} ${chalk.gray("(no tests)")}`;
   }
 
   for (const result of results.sort(sortTests)) {
@@ -307,13 +303,8 @@ export async function renderTestReport(
     }
 
     firstRow.push(basename(entrypoint));
-
-    if (result.path?.length > 0) {
-      firstRow.push(chalk.gray("»"));
-      firstRow.push(chalk.whiteBright(result.path.padEnd(longestPath)));
-    } else {
-      firstRow.push(chalk.gray("(no tests)"));
-    }
+    firstRow.push(chalk.gray("»"));
+    firstRow.push(chalk.whiteBright(result.path.padEnd(longestPath)));
 
     // okay we are ready to print the test result