Add some more unit tests for "filesystem" utility module (#1157)

* Add some more unit tests for "filesystem" utility module

* Lower some tests from integration to the unit level
* Template the expandFilePathTilda function to not mock platform paths
* Add more tests

* Filx spelling

Author: award999

src/toolchain/toolchain.ts

@@ -20,7 +20,7 @@ import * as vscode from "vscode";
 import configuration from "../configuration";
 import { SwiftOutputChannel } from "../ui/SwiftOutputChannel";
 import { execFile, execSwift } from "../utilities/utilities";
-import { expandFilePathTilda, pathExists } from "../utilities/filesystem";
+import { expandFilePathTilde, pathExists } from "../utilities/filesystem";
 import { Version } from "../utilities/version";
 import { BuildFlags } from "./BuildFlags";
 import { Sanitizer } from "./Sanitizer";
@@ -536,7 +536,7 @@ export class SwiftToolchain {
             }
             // swift may be a symbolic link
             const realSwift = await fs.realpath(swift);
-            const swiftPath = expandFilePathTilda(path.dirname(realSwift));
+            const swiftPath = expandFilePathTilde(path.dirname(realSwift));
             return await this.getSwiftEnvPath(swiftPath);
         } catch {
             throw Error("Failed to find swift executable");

src/utilities/filesystem.ts

@@ -58,9 +58,22 @@ export function isPathInsidePath(subpath: string, parent: string): boolean {
  * @param filepath File path
  * @returns full path
  */
-export function expandFilePathTilda(filepath: string): string {
-    if (process.platform !== "win32" && filepath[0] === "~" && process.env.HOME) {
-        return path.join(process.env.HOME, filepath.slice(1));
+export function expandFilePathTilde(
+    filepath: string,
+    directory: string | null = process.env.HOME ?? null,
+    platform: NodeJS.Platform = process.platform
+): string {
+    // Guard no expanding on windows
+    if (platform === "win32") {
+        return filepath;
     }
-    return filepath;
+    // Guard tilde is present
+    if (filepath[0] !== "~") {
+        return filepath;
+    }
+    // Guard we know home directory
+    if (!directory) {
+        return filepath;
+    }
+    return path.join(directory, filepath.slice(1));
 }

test/integration-tests/utilities/filesystem.test.ts

@@ -14,31 +14,9 @@
 
 import * as assert from "assert";
 import * as path from "path";
-import {
-    isPathInsidePath,
-    expandFilePathTilda,
-    fileExists,
-    pathExists,
-} from "../../../src/utilities/filesystem";
+import { fileExists, pathExists } from "../../../src/utilities/filesystem";
 
 suite("File System Utilities Test Suite", () => {
-    test("isPathInsidePath", () => {
-        assert(isPathInsidePath("/home/user/package", "/home/user/"));
-        assert(isPathInsidePath("/home/user/package/test", "/home/user/"));
-        assert(isPathInsidePath("/home/user/", "/home/user/"));
-        assert(isPathInsidePath("/home/user/.build", "/home/user/"));
-        assert(!isPathInsidePath("/home/user/package", "/home/user/package2"));
-        assert(!isPathInsidePath("/home/user/package/.build", "/home/user/package2/.build"));
-        assert(!isPathInsidePath("/home/user/package/", "/home/user/package/.build"));
-    });
-
-    test("expandFilePathTilda", () => {
-        const homeDir = process.env.HOME;
-        assert(expandFilePathTilda("~/Test"), `${homeDir}/Test`);
-        assert(expandFilePathTilda("/Users/John/Test"), `/Users/John/Test`);
-        assert(expandFilePathTilda("/Users/~/Test"), `/Users/~/Test`);
-    });
-
     test("fileExists", async () => {
         assert(await fileExists(__filename));
         assert(!(await fileExists(__dirname)));

test/unit-tests/utilities/filesystem.test.ts

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2024 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import { isPathInsidePath, expandFilePathTilde } from "../../../src/utilities/filesystem";
+import { expect } from "chai";
+
+suite("File System Utilities Unit Test Suite", () => {
+    test("isPathInsidePath", () => {
+        expect(isPathInsidePath("/home/user/package", "/home/user/")).to.be.true;
+        expect(isPathInsidePath("/home/user/package/test", "/home/user/")).to.be.true;
+        expect(isPathInsidePath("/home/user/", "/home/user/")).to.be.true;
+        expect(isPathInsidePath("/home/user/.build", "/home/user/")).to.be.true;
+        expect(isPathInsidePath("/home/user/package", "/home/user/package2")).to.be.false;
+        expect(isPathInsidePath("/home/user/package/.build", "/home/user/package2/.build")).to.be
+            .false;
+        expect(isPathInsidePath("/home/user/package/", "/home/user/package/.build")).to.be.false;
+    });
+
+    suite("expandFilePathTilde", () => {
+        test("expands tilde", () => {
+            expect(expandFilePathTilde("~/Test", "/Users/John", "darwin")).to.equal(
+                "/Users/John/Test"
+            );
+        });
+
+        test("no tilde present", () => {
+            expect(expandFilePathTilde("/Users/John/Test", "/Users/John2", "darwin")).to.equal(
+                "/Users/John/Test"
+            );
+        });
+
+        test("tilde not first character", () => {
+            expect(expandFilePathTilde("/Users/~/Test", "/Users/John", "darwin")).to.equal(
+                "/Users/~/Test"
+            );
+        });
+
+        test("don't know the home directory", () => {
+            expect(expandFilePathTilde("~/Test", null, "darwin")).to.equal("~/Test");
+        });
+
+        test("don't resolve tilde on Windows", () => {
+            expect(expandFilePathTilde("~/Test", "C:\\Users\\John", "win32")).to.equal("~/Test");
+        });
+    });
+});