Added test package in nix flake to automatically run tests.

To be able to do such, it was required to add the vendor directory
to the git project.

vendor/deno.land/std@0.191.0/streams/_common.ts

@@ -0,0 +1,26 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+export const DEFAULT_CHUNK_SIZE = 16_640;
+export const DEFAULT_BUFFER_SIZE = 32 * 1024;
+
+/** Generate longest proper prefix which is also suffix array. */
+export function createLPS(pat: Uint8Array): Uint8Array {
+  const lps = new Uint8Array(pat.length);
+  lps[0] = 0;
+  let prefixEnd = 0;
+  let i = 1;
+  while (i < lps.length) {
+    if (pat[i] == pat[prefixEnd]) {
+      prefixEnd++;
+      lps[i] = prefixEnd;
+      i++;
+    } else if (prefixEnd === 0) {
+      lps[i] = 0;
+      i++;
+    } else {
+      prefixEnd = lps[prefixEnd - 1];
+    }
+  }
+  return lps;
+}