diff --git a/package.json b/package.json
index a4e48e9..65ba239 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,7 @@
     "build": "yarn build-lib && yarn build-types",
     "build:release": "yarn clean && yarn build && yarn build-web",
     "build-lib": "babel src -x .ts -d lib",
-    "build-types": "tsc --declaration --incremental --outDir lib --emitDeclarationOnly",
+    "build-types": "tsc --declaration --incremental --outDir lib --project tsconfig.build.json --emitDeclarationOnly",
     "build-web": "webpack --mode production --entry ./lib/web.js --output ./dist/bls.min.js",
     "check-types": "tsc --noEmit",
     "lint": "eslint --color --ext .ts src/ test/",
diff --git a/tsconfig.build.json b/tsconfig.build.json
new file mode 100644
index 0000000..7e92fee
--- /dev/null
+++ b/tsconfig.build.json
@@ -0,0 +1,5 @@
+{
+  "extends": "./tsconfig",
+  "include": ["src"],
+  "exclude": ["test"],
+}
diff --git a/tsconfig.json b/tsconfig.json
index db678b5..a083043 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,5 +1,5 @@
 {
-  "include": ["src"],
+  "include": ["src", "test"],
   "compilerOptions": {
     "target": "esnext",
     "module": "commonjs",