diff --git a/.gitignore b/.gitignore
index 88686a3..d50310f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 /browser
 /examples/*.js
 /node_modules
+/coverage
+/.nyc_output
diff --git a/lib/compiler/passes/generate-js.js b/lib/compiler/passes/generate-js.js
index adede63..07fc570 100644
--- a/lib/compiler/passes/generate-js.js
+++ b/lib/compiler/passes/generate-js.js
@@ -427,6 +427,7 @@ function generateJS( ast, options ) {
             "          ip++;",
             "          break;",
             "",
+            "        // istanbul ignore next",
             "        default:",
             "          throw new Error(\"Invalid opcode: \" + bc[ip] + \".\");",
             "      }",
@@ -533,6 +534,7 @@ function generateJS( ast, options ) {
                     elseSp = stack.sp;
                     ip += elseLength;
 
+                    // istanbul ignore if
                     if ( thenSp !== elseSp ) {
 
                         throw new Error(
@@ -567,6 +569,7 @@ function generateJS( ast, options ) {
                 bodySp = stack.sp;
                 ip += bodyLength;
 
+                // istanbul ignore if
                 if ( bodySp !== baseSp ) {
 
                     throw new Error( "Body of a loop can't move the stack pointer." );
@@ -780,6 +783,7 @@ function generateJS( ast, options ) {
                         ip++;
                         break;
 
+                    // istanbul ignore next
                     default:
                         throw new Error( "Invalid opcode: " + bc[ ip ] + "." );
 
@@ -843,6 +847,7 @@ function generateJS( ast, options ) {
             "  this.location = location;",
             "  this.name = \"SyntaxError\";",
             "",
+            "  // istanbul ignore next",
             "  if (typeof Error.captureStackTrace === \"function\") {",
             "    Error.captureStackTrace(this, peg$SyntaxError);",
             "  }",
@@ -1003,6 +1008,7 @@ function generateJS( ast, options ) {
                 "      log(event);",
                 "      break;",
                 "",
+                "    // istanbul ignore next",
                 "    default:",
                 "      throw new Error(\"Invalid event type: \" + event.type + \".\");",
                 "  }",
diff --git a/lib/parser.js b/lib/parser.js
index e5678c1..5d7dd7f 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -17,6 +17,7 @@ function peg$SyntaxError(message, expected, found, location) {
   this.location = location;
   this.name = "SyntaxError";
 
+  // istanbul ignore next
   if (typeof Error.captureStackTrace === "function") {
     Error.captureStackTrace(this, peg$SyntaxError);
   }
diff --git a/package.json b/package.json
index 67942b0..f8446a6 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,7 @@
         "clean": "gulp clean",
         "test:impact": "node test/impact",
         "test:server": "node test/server/run",
-        "test": "gulp"
+        "test": "nyc gulp"
     },
     "devDependencies": {
         "babel-preset-es2015": "6.24.1",
@@ -50,6 +50,7 @@
         "gulp-rename": "1.2.2",
         "gulp-uglify": "3.0.0",
         "morgan": "1.9.0",
+        "nyc": "11.3.0",
         "run-sequence": "2.2.0",
         "sinon": "4.1.3",
         "vinyl-buffer": "1.0.0",
@@ -57,5 +58,16 @@
     },
     "engines": {
         "node": ">=4"
+    },
+    "nyc": {
+        "exclude": [
+            "test",
+            "gulpfile.js",
+            "**/.eslintrc.js"
+        ],
+        "reporter": [
+          "text",
+          "text-summary"
+        ]
     }
 }