add stryker, test for timeout valid signature

.gitignore

@@ -2,3 +2,6 @@
 /dist/
 /.nyc_output/
 /coverage/
+
+# stryker temp files
+.stryker-tmp

package.json

@@ -6,6 +6,8 @@
   "license": "MIT",
   "devDependencies": {
     "@scode/eslint-config": "^1.2.25",
+    "@stryker-mutator/core": "^2.5.0",
+    "@stryker-mutator/javascript-mutator": "^2.5.0",
     "ava": "^3.5.0",
     "eslint": "^6.8.0",
     "nyc": "^15.0.0"

stryker.conf.js

@@ -0,0 +1,11 @@
+module.exports = function(config) {
+  config.set({
+    mutator: "javascript",
+    packageManager: "yarn",
+    reporters: ["clear-text"],
+    testRunner: "command",
+    transpilers: [],
+    coverageAnalysis: "all",
+    mutate: ["index.js"]
+  });
+};

test/index.js

@@ -103,6 +103,16 @@ test ('reject old signatures', async (t) => {
   t.is (dec, null);
 });
 
+test ('do not reject valid signatures', async (t) => {
+  const obj = { foo: 'bar' };
+  const str = crypto.sign_object (obj, 'baz');
+  await new Promise ((res) => {
+    setTimeout (res, 10);
+  });
+  const dec = crypto.verify_signature (str, 'baz', 100);
+  t.deepEqual (obj, dec);
+});
+
 test ('decode problematic token', (t) => {
   // eslint-disable-next-line max-len
   const str = 'eyJpYXQiOjE1ODE0NDAwMTIyODgsIm9iaiI6eyJpZCI6MX19.24ZOsWrnfkNe%2FbM0r7DaVJMqE2bfn2aAM%2BZSzWeSf31OCTlXXNWD34RBL2X5v3UliYQ4IIsLNBFbaW9texPHug%3D%3D';