diff --git a/Makefile b/Makefile
index 7bd45b86d..211be1435 100644
--- a/Makefile
+++ b/Makefile
@@ -47,7 +47,7 @@ check: tsc yarn-install
 
 .PHONY: coverage
 coverage: tsc yarn-install
-	$(nyc) $(ava) 'build/**/*-test.js'
+	$(nyc) --all $(ava) 'build/**/*-test.js'
 
 
 
diff --git a/package.json b/package.json
index b2c969117..b4ca383af 100644
--- a/package.json
+++ b/package.json
@@ -16,6 +16,9 @@
   "nyc": {
     "exclude": [
       "emscripten"
+    ],
+    "include": [
+      "build/src/**/*.js"
     ]
   },
   "devDependencies": {