From 70a94af62a84fae53eab29b3377d2076d858c93c Mon Sep 17 00:00:00 2001
From: Nystik <236107-Nystik@users.noreply.gitlab.com>
Date: Thu, 9 Apr 2026 01:02:53 +0200
Subject: [PATCH] add a few more tests

---
 src/shims/fs/content-cache.test.js |  92 ++++++++++
 src/shims/fs/fd.test.js            | 275 +++++++++++++++++++++++++++++
 2 files changed, 367 insertions(+)
 create mode 100644 src/shims/fs/content-cache.test.js
 create mode 100644 src/shims/fs/fd.test.js

diff --git a/src/shims/fs/content-cache.test.js b/src/shims/fs/content-cache.test.js
new file mode 100644
index 0000000..396c344
--- /dev/null
+++ b/src/shims/fs/content-cache.test.js
@@ -0,0 +1,92 @@
+import { describe, it, expect, vi } from "vitest";
+import { ContentCache } from "./content-cache.js";
+
+// -- Size accounting ---------------------------------------------------
+
+describe("ContentCache size accounting", () => {
+  it("set increases currentBytes by data length", () => {
+    const cache = new ContentCache(1024);
+    cache.set("a.md", "hello"); // 5 bytes
+    expect(cache.currentBytes).toBe(5);
+  });
+
+  it("delete returns currentBytes to 0", () => {
+    const cache = new ContentCache(1024);
+    cache.set("a.md", "hello");
+    cache.delete("a.md");
+    expect(cache.currentBytes).toBe(0);
+  });
+
+  it("replacing an entry reflects the new size, not old + new", () => {
+    const cache = new ContentCache(1024);
+    cache.set("a.md", "short");
+    cache.set("a.md", "a much longer string");
+    expect(cache.currentBytes).toBe("a much longer string".length);
+  });
+
+  it("deleting one of several entries leaves the sum of the rest", () => {
+    const cache = new ContentCache(1024);
+    cache.set("a.md", "aaa"); // 3
+    cache.set("b.md", "bbbbb"); // 5
+    cache.set("c.md", "cc"); // 2
+    cache.delete("b.md");
+    expect(cache.currentBytes).toBe(5); // 3 + 2
+  });
+});
+
+// -- LRU eviction ------------------------------------------------------
+
+describe("ContentCache LRU eviction", () => {
+  it("evicts the least-recently-accessed entry when full", () => {
+    let now = 1000;
+    vi.spyOn(Date, "now").mockImplementation(() => now++);
+
+    const cache = new ContentCache(10);
+    cache.set("a.md", "aaaa"); // 4
+    cache.set("b.md", "bbbb"); // 4
+    // At 8/10. Adding 4 more would exceed, so LRU (a.md) should be evicted.
+    cache.set("c.md", "cccc"); // 4
+    expect(cache.has("a.md")).toBe(false);
+    expect(cache.has("b.md")).toBe(true);
+    expect(cache.has("c.md")).toBe(true);
+
+    vi.restoreAllMocks();
+  });
+
+  it("accessing an entry refreshes it so it survives eviction", () => {
+    let now = 1000;
+    vi.spyOn(Date, "now").mockImplementation(() => now++);
+
+    const cache = new ContentCache(10);
+    cache.set("a.md", "aaaa"); // 4, accessedAt=1000
+    cache.set("b.md", "bbbb"); // 4, accessedAt=1001
+    // Touch a.md so b.md becomes the LRU
+    cache.get("a.md"); // a.md accessedAt=1002
+    cache.set("c.md", "cccc"); // 4 -- should evict b.md (1001), not a.md (1002)
+    expect(cache.has("a.md")).toBe(true);
+    expect(cache.has("b.md")).toBe(false);
+    expect(cache.has("c.md")).toBe(true);
+
+    vi.restoreAllMocks();
+  });
+
+  it("entry larger than maxSize still gets stored", () => {
+    const cache = new ContentCache(5);
+    cache.set("small.md", "ab"); // 2
+    cache.set("big.md", "abcdefghij"); // 10 -- larger than maxSize
+    expect(cache.has("small.md")).toBe(false);
+    expect(cache.has("big.md")).toBe(true);
+    expect(cache.currentBytes).toBe(10);
+  });
+});
+
+// -- Path normalization ------------------------------------------------
+
+describe("ContentCache path normalization", () => {
+  it("backslash and slash variants hit the same cache entry", () => {
+    const cache = new ContentCache(1024);
+    cache.set("foo\\bar\\baz.md", "content");
+    expect(cache.has("foo/bar/baz.md")).toBe(true);
+    expect(cache.get("foo/bar/baz.md")).toBe("content");
+  });
+});
diff --git a/src/shims/fs/fd.test.js b/src/shims/fs/fd.test.js
new file mode 100644
index 0000000..bdcb2cc
--- /dev/null
+++ b/src/shims/fs/fd.test.js
@@ -0,0 +1,275 @@
+import { describe, it, expect } from "vitest";
+import { createFdOps } from "./fd.js";
+
+function makeStubs(files = {}) {
+  const meta = {
+    has(p) {
+      return p in files;
+    },
+    toStat(p) {
+      if (!(p in files)) {
+        return null;
+      }
+
+      return {
+        size: files[p].length,
+        isFile: () => true,
+        isDirectory: () => false,
+      };
+    },
+  };
+
+  const content = {
+    _store: {},
+    get(p) {
+      return this._store[p] ?? null;
+    },
+    set(p, data) {
+      this._store[p] = data;
+    },
+  };
+
+  const transport = {
+    readFileSync(p) {
+      return files[p] ?? null;
+    },
+  };
+
+  // Pre-populate content cache so ensureData doesn't hit transport
+  for (const [p, data] of Object.entries(files)) {
+    content.set(p, data);
+  }
+
+  return { meta, content, transport };
+}
+
+function makeOps(files = {}) {
+  const { meta, content, transport } = makeStubs(files);
+  return createFdOps(meta, content, transport);
+}
+
+// -- openSync / closeSync lifecycle ------------------------------------
+
+describe("fd openSync / closeSync lifecycle", () => {
+  it("open returns an integer fd", () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1, 2, 3]) });
+    const fd = ops.openSync("a.md", "r");
+    expect(typeof fd).toBe("number");
+    expect(Number.isInteger(fd)).toBe(true);
+  });
+
+  it("multiple opens return distinct fds", () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1]) });
+    const fd1 = ops.openSync("a.md", "r");
+    const fd2 = ops.openSync("a.md", "r");
+    expect(fd1).not.toBe(fd2);
+  });
+
+  it("close removes the fd", () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1]) });
+    const fd = ops.openSync("a.md", "r");
+    ops.closeSync(fd);
+    expect(() => ops.readSync(fd, new Uint8Array(1), 0, 1, 0)).toThrow(
+      "EBADF",
+    );
+  });
+
+  it("open throws ENOENT for missing path", () => {
+    const ops = makeOps({});
+    expect(() => ops.openSync("nope.md", "r")).toThrow("ENOENT");
+  });
+
+  it("accessing a closed fd throws EBADF", () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1]) });
+    const fd = ops.openSync("a.md", "r");
+    ops.closeSync(fd);
+    expect(() => ops.fstatSync(fd)).toThrow("EBADF");
+  });
+});
+
+// -- readSync ----------------------------------------------------------
+
+describe("fd readSync", () => {
+  const data = new Uint8Array([10, 20, 30, 40, 50]);
+
+  function openData() {
+    const ops = makeOps({ "f.bin": data });
+    const fd = ops.openSync("f.bin", "r");
+    return { ops, fd };
+  }
+
+  it("read from position 0, full length", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(5);
+    const n = ops.readSync(fd, buf, 0, 5, 0);
+    expect(n).toBe(5);
+    expect(buf).toEqual(data);
+  });
+
+  it("read from mid-file position", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(3);
+    const n = ops.readSync(fd, buf, 0, 3, 2);
+    expect(n).toBe(3);
+    expect(buf).toEqual(new Uint8Array([30, 40, 50]));
+  });
+
+  it("read with length exceeding remaining data", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(10);
+    const n = ops.readSync(fd, buf, 0, 10, 3);
+    expect(n).toBe(2);
+    expect(buf[0]).toBe(40);
+    expect(buf[1]).toBe(50);
+  });
+
+  it("read at position === data.length returns 0 bytes", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(5);
+    const n = ops.readSync(fd, buf, 0, 5, 5);
+    expect(n).toBe(0);
+  });
+
+  it("read at position > data.length returns 0 bytes", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(5);
+    const n = ops.readSync(fd, buf, 0, 5, 100);
+    expect(n).toBe(0);
+  });
+
+  it("read with offset > 0 places data at correct position", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(6);
+    buf.fill(0);
+    const n = ops.readSync(fd, buf, 3, 2, 0);
+    expect(n).toBe(2);
+    expect(buf).toEqual(new Uint8Array([0, 0, 0, 10, 20, 0]));
+  });
+
+  it("target buffer is actually modified", () => {
+    const { ops, fd } = openData();
+    const buf = new Uint8Array(3);
+    buf.fill(255);
+    ops.readSync(fd, buf, 0, 2, 0);
+    expect(buf[0]).toBe(10);
+    expect(buf[1]).toBe(20);
+    expect(buf[2]).toBe(255); // untouched
+  });
+});
+
+// -- fstatSync ---------------------------------------------------------
+
+describe("fd fstatSync", () => {
+  it("returns metadata from cache when available", () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1, 2, 3]) });
+    const fd = ops.openSync("a.md", "r");
+    const stat = ops.fstatSync(fd);
+    expect(stat.size).toBe(3);
+    expect(stat.isFile()).toBe(true);
+    expect(stat.isDirectory()).toBe(false);
+  });
+
+  it("falls back to buffer length when metadata is missing", () => {
+    const { meta, content, transport } = makeStubs({
+      "a.md": new Uint8Array([1, 2, 3, 4]),
+    });
+
+    // Override toStat to return null, simulating missing metadata
+    meta.toStat = () => null;
+
+    const ops = createFdOps(meta, content, transport);
+    const fd = ops.openSync("a.md", "r");
+    const stat = ops.fstatSync(fd);
+    expect(stat.size).toBe(4);
+    expect(stat.isFile()).toBe(true);
+  });
+});
+
+// -- Async wrappers ----------------------------------------------------
+
+describe("fd async wrappers", () => {
+  it("open() calls callback asynchronously", async () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1]) });
+    let called = false;
+
+    const promise = new Promise((resolve, reject) => {
+      ops.open("a.md", "r", (err, fd) => {
+        called = true;
+
+        if (err) {
+          reject(err);
+        } else {
+          resolve(fd);
+        }
+      });
+    });
+
+    // Callback should not have fired synchronously
+    expect(called).toBe(false);
+    const fd = await promise;
+    expect(typeof fd).toBe("number");
+  });
+
+  it("open() error path calls cb(err)", async () => {
+    const ops = makeOps({});
+
+    const err = await new Promise((resolve) => {
+      ops.open("nope.md", "r", (e) => resolve(e));
+    });
+
+    expect(err).toBeTruthy();
+    expect(err.code).toBe("ENOENT");
+  });
+
+  it("read() delivers results via callback", async () => {
+    const ops = makeOps({ "a.md": new Uint8Array([10, 20]) });
+
+    const fd = await new Promise((resolve, reject) => {
+      ops.open("a.md", "r", (err, fd) => (err ? reject(err) : resolve(fd)));
+    });
+
+    const buf = new Uint8Array(2);
+
+    const bytesRead = await new Promise((resolve, reject) => {
+      ops.read(fd, buf, 0, 2, 0, (err, n) =>
+        err ? reject(err) : resolve(n),
+      );
+    });
+
+    expect(bytesRead).toBe(2);
+    expect(buf).toEqual(new Uint8Array([10, 20]));
+  });
+
+  it("close() calls callback asynchronously", async () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1]) });
+    const fd = ops.openSync("a.md", "r");
+
+    const result = await new Promise((resolve) => {
+      ops.close(fd, (err) => resolve(err));
+    });
+
+    expect(result).toBe(null);
+  });
+
+  it("fstat() calls callback asynchronously", async () => {
+    const ops = makeOps({ "a.md": new Uint8Array([1, 2, 3]) });
+    const fd = ops.openSync("a.md", "r");
+
+    const stat = await new Promise((resolve, reject) => {
+      ops.fstat(fd, (err, s) => (err ? reject(err) : resolve(s)));
+    });
+
+    expect(stat.size).toBe(3);
+  });
+
+  it("fstat() error path calls cb(err) for bad fd", async () => {
+    const ops = makeOps({});
+
+    const err = await new Promise((resolve) => {
+      ops.fstat(99999, (e) => resolve(e));
+    });
+
+    expect(err).toBeTruthy();
+    expect(err.code).toBe("EBADF");
+  });
+});