diff --git a/src/infra/infra-runtime.test.ts b/src/infra/infra-runtime.test.ts
index 66a81f7bc06..6676a5d8f8a 100644
--- a/src/infra/infra-runtime.test.ts
+++ b/src/infra/infra-runtime.test.ts
@@ -224,35 +224,34 @@ describe("infra runtime", () => {
     afterEach(() => resetShellPathCacheForTests());
 
     it("returns PATH from login shell env", () => {
-      if (process.platform === "win32") {
-        return;
-      }
       const exec = vi
         .fn()
         .mockReturnValue(Buffer.from("PATH=/custom/bin\0HOME=/home/user\0", "utf-8"));
-      const result = getShellPathFromLoginShell({ env: { SHELL: "/bin/sh" }, exec });
+      const result = getShellPathFromLoginShell({
+        env: { SHELL: "/bin/sh" },
+        exec,
+        platform: "linux",
+      });
       expect(result).toBe("/custom/bin");
     });
 
     it("caches the value", () => {
-      if (process.platform === "win32") {
-        return;
-      }
       const exec = vi.fn().mockReturnValue(Buffer.from("PATH=/custom/bin\0", "utf-8"));
       const env = { SHELL: "/bin/sh" } as NodeJS.ProcessEnv;
-      expect(getShellPathFromLoginShell({ env, exec })).toBe("/custom/bin");
-      expect(getShellPathFromLoginShell({ env, exec })).toBe("/custom/bin");
+      expect(getShellPathFromLoginShell({ env, exec, platform: "linux" })).toBe("/custom/bin");
+      expect(getShellPathFromLoginShell({ env, exec, platform: "linux" })).toBe("/custom/bin");
       expect(exec).toHaveBeenCalledTimes(1);
     });
 
     it("returns null on exec failure", () => {
-      if (process.platform === "win32") {
-        return;
-      }
       const exec = vi.fn(() => {
         throw new Error("boom");
       });
-      const result = getShellPathFromLoginShell({ env: { SHELL: "/bin/sh" }, exec });
+      const result = getShellPathFromLoginShell({
+        env: { SHELL: "/bin/sh" },
+        exec,
+        platform: "linux",
+      });
       expect(result).toBeNull();
     });
   });
diff --git a/src/infra/shell-env.test.ts b/src/infra/shell-env.test.ts
index 1a3449900be..0869dfec4f9 100644
--- a/src/infra/shell-env.test.ts
+++ b/src/infra/shell-env.test.ts
@@ -81,19 +81,14 @@ describe("shell env fallback", () => {
     const first = getShellPathFromLoginShell({
       env: {} as NodeJS.ProcessEnv,
       exec: exec as unknown as Parameters<typeof getShellPathFromLoginShell>[0]["exec"],
+      platform: "linux",
     });
     const second = getShellPathFromLoginShell({
       env: {} as NodeJS.ProcessEnv,
       exec: exec as unknown as Parameters<typeof getShellPathFromLoginShell>[0]["exec"],
+      platform: "linux",
     });
 
-    if (process.platform === "win32") {
-      expect(first).toBeNull();
-      expect(second).toBeNull();
-      expect(exec).not.toHaveBeenCalled();
-      return;
-    }
-
     expect(first).toBe("/usr/local/bin:/usr/bin");
     expect(second).toBe("/usr/local/bin:/usr/bin");
     expect(exec).toHaveBeenCalledOnce();
@@ -108,18 +103,36 @@ describe("shell env fallback", () => {
     const first = getShellPathFromLoginShell({
       env: {} as NodeJS.ProcessEnv,
       exec: exec as unknown as Parameters<typeof getShellPathFromLoginShell>[0]["exec"],
+      platform: "linux",
     });
     const second = getShellPathFromLoginShell({
       env: {} as NodeJS.ProcessEnv,
       exec: exec as unknown as Parameters<typeof getShellPathFromLoginShell>[0]["exec"],
+      platform: "linux",
     });
 
     expect(first).toBeNull();
     expect(second).toBeNull();
-    if (process.platform === "win32") {
-      expect(exec).not.toHaveBeenCalled();
-      return;
-    }
     expect(exec).toHaveBeenCalledOnce();
   });
+
+  it("returns null without invoking shell on win32", () => {
+    resetShellPathCacheForTests();
+    const exec = vi.fn(() => Buffer.from("PATH=/usr/local/bin:/usr/bin\0HOME=/tmp\0"));
+
+    const first = getShellPathFromLoginShell({
+      env: {} as NodeJS.ProcessEnv,
+      exec: exec as unknown as Parameters<typeof getShellPathFromLoginShell>[0]["exec"],
+      platform: "win32",
+    });
+    const second = getShellPathFromLoginShell({
+      env: {} as NodeJS.ProcessEnv,
+      exec: exec as unknown as Parameters<typeof getShellPathFromLoginShell>[0]["exec"],
+      platform: "win32",
+    });
+
+    expect(first).toBeNull();
+    expect(second).toBeNull();
+    expect(exec).not.toHaveBeenCalled();
+  });
 });
diff --git a/src/infra/shell-env.ts b/src/infra/shell-env.ts
index d1fa53fe01c..51839c66ea9 100644
--- a/src/infra/shell-env.ts
+++ b/src/infra/shell-env.ts
@@ -140,11 +140,13 @@ export function getShellPathFromLoginShell(opts: {
   env: NodeJS.ProcessEnv;
   timeoutMs?: number;
   exec?: typeof execFileSync;
+  platform?: NodeJS.Platform;
 }): string | null {
   if (cachedShellPath !== undefined) {
     return cachedShellPath;
   }
-  if (process.platform === "win32") {
+  const platform = opts.platform ?? process.platform;
+  if (platform === "win32") {
     cachedShellPath = null;
     return cachedShellPath;
   }