1 files changed, 195 insertions, 0 deletions
diff --git a/tests/unit/link_test.ts b/tests/unit/link_test.ts
new file mode 100644
index 000000000..6048b8add
--- /dev/null
+++ b/tests/unit/link_test.ts
@@ -0,0 +1,195 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+import {
+  assert,
+  assertEquals,
+  assertRejects,
+  assertThrows,
+} from "./test_util.ts";
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  function linkSyncSuccess() {
+    const testDir = Deno.makeTempDirSync();
+    const oldData = "Hardlink";
+    const oldName = testDir + "/oldname";
+    const newName = testDir + "/newname";
+    Deno.writeFileSync(oldName, new TextEncoder().encode(oldData));
+    // Create the hard link.
+    Deno.linkSync(oldName, newName);
+    // We should expect reading the same content.
+    const newData = Deno.readTextFileSync(newName);
+    assertEquals(oldData, newData);
+    // Writing to newname also affects oldname.
+    const newData2 = "Modified";
+    Deno.writeFileSync(newName, new TextEncoder().encode(newData2));
+    assertEquals(
+      newData2,
+      Deno.readTextFileSync(oldName),
+    );
+    // Writing to oldname also affects newname.
+    const newData3 = "ModifiedAgain";
+    Deno.writeFileSync(oldName, new TextEncoder().encode(newData3));
+    assertEquals(
+      newData3,
+      Deno.readTextFileSync(newName),
+    );
+    // Remove oldname. File still accessible through newname.
+    Deno.removeSync(oldName);
+    const newNameStat = Deno.statSync(newName);
+    assert(newNameStat.isFile);
+    assert(!newNameStat.isSymlink); // Not a symlink.
+    assertEquals(
+      newData3,
+      Deno.readTextFileSync(newName),
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  function linkSyncExists() {
+    const testDir = Deno.makeTempDirSync();
+    const oldName = testDir + "/oldname";
+    const newName = testDir + "/newname";
+    Deno.writeFileSync(oldName, new TextEncoder().encode("oldName"));
+    // newname is already created.
+    Deno.writeFileSync(newName, new TextEncoder().encode("newName"));
+
+    assertThrows(
+      () => {
+        Deno.linkSync(oldName, newName);
+      },
+      Deno.errors.AlreadyExists,
+      `link '${oldName}' -> '${newName}'`,
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  function linkSyncNotFound() {
+    const testDir = Deno.makeTempDirSync();
+    const oldName = testDir + "/oldname";
+    const newName = testDir + "/newname";
+
+    assertThrows(
+      () => {
+        Deno.linkSync(oldName, newName);
+      },
+      Deno.errors.NotFound,
+      `link '${oldName}' -> '${newName}'`,
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: false, write: true } },
+  function linkSyncReadPerm() {
+    assertThrows(() => {
+      Deno.linkSync("oldbaddir", "newbaddir");
+    }, Deno.errors.PermissionDenied);
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: false } },
+  function linkSyncWritePerm() {
+    assertThrows(() => {
+      Deno.linkSync("oldbaddir", "newbaddir");
+    }, Deno.errors.PermissionDenied);
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  async function linkSuccess() {
+    const testDir = Deno.makeTempDirSync();
+    const oldData = "Hardlink";
+    const oldName = testDir + "/oldname";
+    const newName = testDir + "/newname";
+    Deno.writeFileSync(oldName, new TextEncoder().encode(oldData));
+    // Create the hard link.
+    await Deno.link(oldName, newName);
+    // We should expect reading the same content.
+    const newData = Deno.readTextFileSync(newName);
+    assertEquals(oldData, newData);
+    // Writing to newname also affects oldname.
+    const newData2 = "Modified";
+    Deno.writeFileSync(newName, new TextEncoder().encode(newData2));
+    assertEquals(
+      newData2,
+      Deno.readTextFileSync(oldName),
+    );
+    // Writing to oldname also affects newname.
+    const newData3 = "ModifiedAgain";
+    Deno.writeFileSync(oldName, new TextEncoder().encode(newData3));
+    assertEquals(
+      newData3,
+      Deno.readTextFileSync(newName),
+    );
+    // Remove oldname. File still accessible through newname.
+    Deno.removeSync(oldName);
+    const newNameStat = Deno.statSync(newName);
+    assert(newNameStat.isFile);
+    assert(!newNameStat.isSymlink); // Not a symlink.
+    assertEquals(
+      newData3,
+      Deno.readTextFileSync(newName),
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  async function linkExists() {
+    const testDir = Deno.makeTempDirSync();
+    const oldName = testDir + "/oldname";
+    const newName = testDir + "/newname";
+    Deno.writeFileSync(oldName, new TextEncoder().encode("oldName"));
+    // newname is already created.
+    Deno.writeFileSync(newName, new TextEncoder().encode("newName"));
+
+    await assertRejects(
+      async () => {
+        await Deno.link(oldName, newName);
+      },
+      Deno.errors.AlreadyExists,
+      `link '${oldName}' -> '${newName}'`,
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: true } },
+  async function linkNotFound() {
+    const testDir = Deno.makeTempDirSync();
+    const oldName = testDir + "/oldname";
+    const newName = testDir + "/newname";
+
+    await assertRejects(
+      async () => {
+        await Deno.link(oldName, newName);
+      },
+      Deno.errors.NotFound,
+      `link '${oldName}' -> '${newName}'`,
+    );
+  },
+);
+
+Deno.test(
+  { permissions: { read: false, write: true } },
+  async function linkReadPerm() {
+    await assertRejects(async () => {
+      await Deno.link("oldbaddir", "newbaddir");
+    }, Deno.errors.PermissionDenied);
+  },
+);
+
+Deno.test(
+  { permissions: { read: true, write: false } },
+  async function linkWritePerm() {
+    await assertRejects(async () => {
+      await Deno.link("oldbaddir", "newbaddir");
+    }, Deno.errors.PermissionDenied);
+  },
+);