1 files changed, 23 insertions, 0 deletions
diff --git a/cli/tests/unit/tty_test.ts b/cli/tests/unit/tty_test.ts
new file mode 100644
index 000000000..116b0dfe9
--- /dev/null
+++ b/cli/tests/unit/tty_test.ts
@@ -0,0 +1,23 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { unitTest, assert } from "./test_util.ts";
+
+// Note tests for Deno.setRaw is in integration tests.
+
+unitTest({ perms: { read: true } }, function isatty(): void {
+  // CI not under TTY, so cannot test stdin/stdout/stderr.
+  const f = Deno.openSync("cli/tests/hello.txt");
+  assert(!Deno.isatty(f.rid));
+  f.close();
+});
+
+unitTest(function isattyError(): void {
+  let caught = false;
+  try {
+    // Absurdly large rid.
+    Deno.isatty(0x7fffffff);
+  } catch (e) {
+    caught = true;
+    assert(e instanceof Deno.errors.BadResource);
+  }
+  assert(caught);
+});