diff --git a/karma.conf.js b/karma.conf.js
index dd9ef4f..054c371 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -18,7 +18,7 @@ module.exports = function(config) {
 
     // list of files / patterns to load in the browser
     files: [
-      "tests/unit/*.spec.js",
+      "./karma.files.js",
       { pattern: 'node_modules/sql.js/dist/sql-wasm.wasm',
         watched: false,
         included: false,
@@ -39,7 +39,7 @@ module.exports = function(config) {
     // preprocess matching files before serving them to the browser
     // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
     preprocessors: {
-      "tests/unit/*.spec.js": ["webpack"]
+      "./karma.files.js": ["webpack"]
     },
 
     // test results reporter to use
@@ -118,7 +118,14 @@ module.exports = function(config) {
             use: [
               {
                 loader: "babel-loader"
-              },
+              }
+            ]
+          },
+          {
+            test: /\.js$/,
+            include: /src/,
+            exclude: /(node_modules|bower_components|\.spec\.js$|\/file)/,
+            use: [
               {
                 loader: "istanbul-instrumenter-loader",
                 options: {
diff --git a/karma.files.js b/karma.files.js
new file mode 100644
index 0000000..7115137
--- /dev/null
+++ b/karma.files.js
@@ -0,0 +1,16 @@
+import Vue from "vue";
+
+Vue.config.productionTip = false;
+
+// require all test files (files that ends with .spec.js)
+const testsContext = require.context("./tests/unit", true, /\.spec.js$/);
+
+// Read more about why we need to call testContext:
+// https://www.npmjs.com/package/require-context#context-api
+testsContext.keys().forEach(testsContext);
+
+// require all src files except main.js for coverage.
+// you can also change this to match only the subset of files that
+// you want coverage for.
+const srcContext = require.context("./src", true, /^\.\/(?!main(\.js)?$)/);
+srcContext.keys().forEach(srcContext);
\ No newline at end of file