Add unit test coverage

Author: codedread

.c8rc

@@ -0,0 +1,19 @@
+{
+  "check-coverage": true,
+  "all": true,
+  "include": [
+    "codecs/*.js",
+    "file/*.js",
+    "io/*.js"
+  ],
+  "exclude": [
+    "io/*-worker.js"
+  ],
+  "reporter": [
+    "html",
+    "lcov",
+    "text",
+    "text-summary"
+  ],
+  "report-dir": "coverage"
+}

.gitignore

@@ -1,2 +1,3 @@
+coverage
 node_modules
 tests/archive.spec.notready.js