diff --git a/src/shared/utils/__tests__/basePath.test.ts b/src/shared/utils/__tests__/basePath.test.ts
deleted file mode 100644
index 2cfa9ecd98..0000000000
--- a/src/shared/utils/__tests__/basePath.test.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import { describe, expect, it } from "vitest";
-import { getDeployBasePath, normalizeBasePath, withBasePath } from "../basePath";
-
-describe("normalizeBasePath", () => {
-  it("normalizes leading/trailing slashes", () => {
-    expect(normalizeBasePath("omniroute")).toBe("/omniroute");
-    expect(normalizeBasePath("/omniroute/")).toBe("/omniroute");
-    expect(normalizeBasePath("/omniroute")).toBe("/omniroute");
-    expect(normalizeBasePath("")).toBe("");
-    expect(normalizeBasePath("/")).toBe("");
-    expect(normalizeBasePath(null)).toBe("");
-  });
-});
-
-describe("getDeployBasePath", () => {
-  it("reads NEXT_PUBLIC_OMNIROUTE_BASE_PATH first", () => {
-    expect(
-      getDeployBasePath({
-        NEXT_PUBLIC_OMNIROUTE_BASE_PATH: "/omniroute",
-        OMNIROUTE_BASE_PATH: "/other",
-      } as NodeJS.ProcessEnv)
-    ).toBe("/omniroute");
-  });
-
-  it("falls back to OMNIROUTE_BASE_PATH", () => {
-    expect(
-      getDeployBasePath({
-        OMNIROUTE_BASE_PATH: "/omniroute",
-      } as NodeJS.ProcessEnv)
-    ).toBe("/omniroute");
-  });
-});
-
-describe("withBasePath", () => {
-  const base = "/omniroute";
-
-  it("is a no-op when basePath is empty", () => {
-    expect(withBasePath("/api/health/ping", "")).toBe("/api/health/ping");
-  });
-
-  it("prefixes absolute app paths", () => {
-    expect(withBasePath("/api/health/ping", base)).toBe("/omniroute/api/health/ping");
-    expect(withBasePath("/v1/models", base)).toBe("/omniroute/v1/models");
-  });
-
-  it("does not double-prefix", () => {
-    expect(withBasePath("/omniroute/api/health/ping", base)).toBe("/omniroute/api/health/ping");
-    expect(withBasePath("/omniroute", base)).toBe("/omniroute");
-  });
-
-  it("rewrites same-origin absolute URLs", () => {
-    expect(withBasePath("https://host.example/api/x", base, "https://host.example")).toBe(
-      "https://host.example/omniroute/api/x"
-    );
-  });
-
-  it("leaves external absolute URLs alone", () => {
-    expect(withBasePath("https://other.example/api/x", base, "https://host.example")).toBe(
-      "https://other.example/api/x"
-    );
-  });
-
-  it("leaves protocol-relative URLs alone", () => {
-    expect(withBasePath("//cdn.example/app.js", base)).toBe("//cdn.example/app.js");
-  });
-});
diff --git a/src/shared/utils/__tests__/basePathFetch.test.ts b/src/shared/utils/__tests__/basePathFetch.test.ts
deleted file mode 100644
index c64d7f6796..0000000000
--- a/src/shared/utils/__tests__/basePathFetch.test.ts
+++ /dev/null
@@ -1,55 +0,0 @@
-// @vitest-environment jsdom
-import { afterEach, describe, expect, it, vi } from "vitest";
-import { __resetBasePathFetchForTests, installBasePathFetch } from "../basePathFetch";
-
-describe("installBasePathFetch", () => {
-  afterEach(() => {
-    __resetBasePathFetchForTests();
-    vi.unstubAllGlobals();
-  });
-
-  it("is a no-op when basePath is empty", async () => {
-    const native = vi.fn(async () => new Response("ok"));
-    vi.stubGlobal("fetch", native);
-
-    const uninstall = installBasePathFetch("");
-    await fetch("/api/health/ping");
-    expect(native).toHaveBeenCalledWith("/api/health/ping", undefined);
-    uninstall();
-  });
-
-  it("prefixes absolute paths on fetch when basePath is set", async () => {
-    const native = vi.fn(async () => new Response("ok"));
-    vi.stubGlobal("fetch", native);
-
-    const uninstall = installBasePathFetch("/omniroute");
-    await fetch("/api/health/ping");
-    expect(native).toHaveBeenCalledWith("/omniroute/api/health/ping", undefined);
-    uninstall();
-  });
-
-  it("does not double-prefix already-prefixed paths", async () => {
-    const native = vi.fn(async () => new Response("ok"));
-    vi.stubGlobal("fetch", native);
-
-    const uninstall = installBasePathFetch("/omniroute");
-    await fetch("/omniroute/api/health/ping");
-    expect(native).toHaveBeenCalledWith("/omniroute/api/health/ping", undefined);
-    uninstall();
-  });
-
-  it("restores native fetch after last uninstall", async () => {
-    const native = vi.fn(async () => new Response("ok"));
-    vi.stubGlobal("fetch", native);
-
-    const a = installBasePathFetch("/omniroute");
-    const b = installBasePathFetch("/omniroute");
-    a();
-    await fetch("/api/x");
-    expect(native).toHaveBeenCalledWith("/omniroute/api/x", undefined);
-    b();
-    native.mockClear();
-    await fetch("/api/x");
-    expect(native).toHaveBeenCalledWith("/api/x", undefined);
-  });
-});
diff --git a/tests/unit/shared/basePath.test.ts b/tests/unit/shared/basePath.test.ts
new file mode 100644
index 0000000000..8b86e95701
--- /dev/null
+++ b/tests/unit/shared/basePath.test.ts
@@ -0,0 +1,75 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import {
+  getDeployBasePath,
+  normalizeBasePath,
+  withBasePath,
+} from "../../../src/shared/utils/basePath";
+
+describe("normalizeBasePath", () => {
+  it("normalizes leading/trailing slashes", () => {
+    assert.equal(normalizeBasePath("omniroute"), "/omniroute");
+    assert.equal(normalizeBasePath("/omniroute/"), "/omniroute");
+    assert.equal(normalizeBasePath("/omniroute"), "/omniroute");
+    assert.equal(normalizeBasePath(""), "");
+    assert.equal(normalizeBasePath("/"), "");
+    assert.equal(normalizeBasePath(null), "");
+  });
+});
+
+describe("getDeployBasePath", () => {
+  it("reads NEXT_PUBLIC_OMNIROUTE_BASE_PATH first", () => {
+    assert.equal(
+      getDeployBasePath({
+        NEXT_PUBLIC_OMNIROUTE_BASE_PATH: "/omniroute",
+        OMNIROUTE_BASE_PATH: "/other",
+      } as NodeJS.ProcessEnv),
+      "/omniroute"
+    );
+  });
+
+  it("falls back to OMNIROUTE_BASE_PATH", () => {
+    assert.equal(
+      getDeployBasePath({
+        OMNIROUTE_BASE_PATH: "/omniroute",
+      } as NodeJS.ProcessEnv),
+      "/omniroute"
+    );
+  });
+});
+
+describe("withBasePath", () => {
+  const base = "/omniroute";
+
+  it("is a no-op when basePath is empty", () => {
+    assert.equal(withBasePath("/api/health/ping", ""), "/api/health/ping");
+  });
+
+  it("prefixes absolute app paths", () => {
+    assert.equal(withBasePath("/api/health/ping", base), "/omniroute/api/health/ping");
+    assert.equal(withBasePath("/v1/models", base), "/omniroute/v1/models");
+  });
+
+  it("does not double-prefix", () => {
+    assert.equal(withBasePath("/omniroute/api/health/ping", base), "/omniroute/api/health/ping");
+    assert.equal(withBasePath("/omniroute", base), "/omniroute");
+  });
+
+  it("rewrites same-origin absolute URLs", () => {
+    assert.equal(
+      withBasePath("https://host.example/api/x", base, "https://host.example"),
+      "https://host.example/omniroute/api/x"
+    );
+  });
+
+  it("leaves external absolute URLs alone", () => {
+    assert.equal(
+      withBasePath("https://other.example/api/x", base, "https://host.example"),
+      "https://other.example/api/x"
+    );
+  });
+
+  it("leaves protocol-relative URLs alone", () => {
+    assert.equal(withBasePath("//cdn.example/app.js", base), "//cdn.example/app.js");
+  });
+});
diff --git a/tests/unit/shared/basePathFetch.test.ts b/tests/unit/shared/basePathFetch.test.ts
new file mode 100644
index 0000000000..5ce000cf90
--- /dev/null
+++ b/tests/unit/shared/basePathFetch.test.ts
@@ -0,0 +1,78 @@
+import assert from "node:assert/strict";
+import { afterEach, describe, it, mock } from "node:test";
+import {
+  __resetBasePathFetchForTests,
+  installBasePathFetch,
+} from "../../../src/shared/utils/basePathFetch";
+
+describe("installBasePathFetch", () => {
+  afterEach(() => {
+    __resetBasePathFetchForTests();
+  });
+
+  it("is a no-op when basePath is empty", async () => {
+    const native = mock.fn(async () => new Response("ok"));
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = native as unknown as typeof fetch;
+    try {
+      const uninstall = installBasePathFetch("");
+      await fetch("/api/health/ping");
+      // No-op install never wraps fetch, so the call keeps its original single-argument
+      // shape (the caller passed no `init`) instead of the two-argument shape the wrapper
+      // produces once basePath is set.
+      assert.deepEqual(native.mock.calls[0].arguments, ["/api/health/ping"]);
+      uninstall();
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
+
+  it("prefixes absolute paths on fetch when basePath is set", async () => {
+    const native = mock.fn(async () => new Response("ok"));
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = native as unknown as typeof fetch;
+    try {
+      const uninstall = installBasePathFetch("/omniroute");
+      await fetch("/api/health/ping");
+      assert.deepEqual(native.mock.calls[0].arguments, ["/omniroute/api/health/ping", undefined]);
+      uninstall();
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
+
+  it("does not double-prefix already-prefixed paths", async () => {
+    const native = mock.fn(async () => new Response("ok"));
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = native as unknown as typeof fetch;
+    try {
+      const uninstall = installBasePathFetch("/omniroute");
+      await fetch("/omniroute/api/health/ping");
+      assert.deepEqual(native.mock.calls[0].arguments, ["/omniroute/api/health/ping", undefined]);
+      uninstall();
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
+
+  it("restores native fetch after last uninstall", async () => {
+    const native = mock.fn(async () => new Response("ok"));
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = native as unknown as typeof fetch;
+    try {
+      const a = installBasePathFetch("/omniroute");
+      const b = installBasePathFetch("/omniroute");
+      a();
+      await fetch("/api/x");
+      assert.deepEqual(native.mock.calls[0].arguments, ["/omniroute/api/x", undefined]);
+      b();
+      native.mock.resetCalls();
+      await fetch("/api/x");
+      // Once the last consumer uninstalls, fetch is native again — same single-argument
+      // call shape as the no-op case above.
+      assert.deepEqual(native.mock.calls[0].arguments, ["/api/x"]);
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
+});