test: add coverage for error apis

Add coverage for N-API functions related to
throwing and creating errors.  A number of these
are currently showing as not having any
coverage in the nightly code coverage reports.

PR-URL: #12729
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/addons-napi/test_error/test.js

@@ -55,3 +55,37 @@ assert.strictEqual(test_error.checkError({}), false,
 // Test that non-error primitive is correctly classed
 assert.strictEqual(test_error.checkError('non-object'), false,
                    'Non-error primitive correctly classed by napi_is_error');
+
+assert.throws(() => {
+  test_error.throwExistingError();
+}, /^Error: existing error$/);
+
+assert.throws(() => {
+  test_error.throwError();
+}, /^Error: error$/);
+
+assert.throws(() => {
+  test_error.throwRangeError();
+}, /^RangeError: range error$/);
+
+assert.throws(() => {
+  test_error.throwTypeError();
+}, /^TypeError: type error$/);
+
+let error = test_error.createError();
+assert.ok(error instanceof Error, 'expected error to be an instance of Error');
+assert.strictEqual(error.message, 'error', 'expected message to be "error"');
+
+error = test_error.createRangeError();
+assert.ok(error instanceof RangeError,
+          'expected error to be an instance of RangeError');
+assert.strictEqual(error.message,
+                   'range error',
+                   'expected message to be "range error"');
+
+error = test_error.createTypeError();
+assert.ok(error instanceof TypeError,
+          'expected error to be an instance of TypeError');
+assert.strictEqual(error.message,
+                   'type error',
+                   'expected message to be "type error"');

test/addons-napi/test_error/test_error.cc

@@ -15,9 +15,64 @@ napi_value checkError(napi_env env, napi_callback_info info) {
   return result;
 }
 
+napi_value throwExistingError(napi_env env, napi_callback_info info) {
+  napi_value message;
+  napi_value error;
+  NAPI_CALL(env, napi_create_string_utf8(env, "existing error", -1, &message));
+  NAPI_CALL(env, napi_create_error(env, message, &error));
+  NAPI_CALL(env, napi_throw(env, error));
+  return nullptr;
+}
+
+napi_value throwError(napi_env env, napi_callback_info info) {
+  NAPI_CALL(env, napi_throw_error(env, "error"));
+  return nullptr;
+}
+
+napi_value throwRangeError(napi_env env, napi_callback_info info) {
+  NAPI_CALL(env, napi_throw_range_error(env, "range error"));
+  return nullptr;
+}
+
+napi_value throwTypeError(napi_env env, napi_callback_info info) {
+  NAPI_CALL(env, napi_throw_type_error(env, "type error"));
+  return nullptr;
+}
+
+napi_value createError(napi_env env, napi_callback_info info) {
+  napi_value result;
+  napi_value message;
+  NAPI_CALL(env, napi_create_string_utf8(env, "error", -1, &message));
+  NAPI_CALL(env, napi_create_error(env, message, &result));
+  return result;
+}
+
+napi_value createRangeError(napi_env env, napi_callback_info info) {
+  napi_value result;
+  napi_value message;
+  NAPI_CALL(env, napi_create_string_utf8(env, "range error", -1, &message));
+  NAPI_CALL(env, napi_create_range_error(env, message, &result));
+  return result;
+}
+
+napi_value createTypeError(napi_env env, napi_callback_info info) {
+  napi_value result;
+  napi_value message;
+  NAPI_CALL(env, napi_create_string_utf8(env, "type error", -1, &message));
+  NAPI_CALL(env, napi_create_type_error(env, message, &result));
+  return result;
+}
+
 void Init(napi_env env, napi_value exports, napi_value module, void* priv) {
   napi_property_descriptor descriptors[] = {
     DECLARE_NAPI_PROPERTY("checkError", checkError),
+    DECLARE_NAPI_PROPERTY("throwExistingError", throwExistingError),
+    DECLARE_NAPI_PROPERTY("throwError", throwError),
+    DECLARE_NAPI_PROPERTY("throwRangeError", throwRangeError),
+    DECLARE_NAPI_PROPERTY("throwTypeError", throwTypeError),
+    DECLARE_NAPI_PROPERTY("createError", createError),
+    DECLARE_NAPI_PROPERTY("createRangeError", createRangeError),
+    DECLARE_NAPI_PROPERTY("createTypeError", createTypeError),
   };
 
   NAPI_CALL_RETURN_VOID(env, napi_define_properties(