diff --git a/cmake/unit_tests.cmake b/cmake/unit_tests.cmake
index 3ded8ae..2c271b5 100644
--- a/cmake/unit_tests.cmake
+++ b/cmake/unit_tests.cmake
@@ -50,6 +50,7 @@ add_executable(alltests
 	test/webfuse/tests/provider/operation/test_close.cc
 	test/webfuse/tests/provider/operation/test_getattr.cc
 	test/webfuse/tests/provider/operation/test_lookup.cc
+	test/webfuse/tests/provider/operation/test_open.cc
 	test/webfuse/tests/integration/test_integration.cc
 	test/webfuse/tests/integration/server.cc
 	test/webfuse/tests/integration/provider.cc
diff --git a/test/webfuse/mocks/mock_request.hpp b/test/webfuse/mocks/mock_request.hpp
index e3476ba..f286409 100644
--- a/test/webfuse/mocks/mock_request.hpp
+++ b/test/webfuse/mocks/mock_request.hpp
@@ -44,6 +44,18 @@ MATCHER_P3(StatMatcher, inode, mode, file_type, "")
     return true;
 }
 
+MATCHER_P(OpenMatcher, handle, "") 
+{
+    json_t * handle_holder = json_object_get(arg, "handle");
+    if ((!json_is_integer(handle_holder)) || (handle != json_integer_value(handle_holder)))
+    {
+        *result_listener << "missing handle";
+        return false;
+    }
+
+    return true;
+}
+
 MATCHER_P(ReaddirMatcher, contained_elements , "") 
 {
     if (!json_is_array(arg))
diff --git a/test/webfuse/tests/provider/operation/test_open.cc b/test/webfuse/tests/provider/operation/test_open.cc
new file mode 100644
index 0000000..68a53f0
--- /dev/null
+++ b/test/webfuse/tests/provider/operation/test_open.cc
@@ -0,0 +1,110 @@
+#include "webfuse/provider/impl/operation/open.h"
+#include "webfuse/mocks/mock_request.hpp"
+#include "webfuse/mocks/mock_provider.hpp"
+#include "webfuse/mocks/fake_invokation_context.hpp"
+
+#include <gtest/gtest.h>
+#include <cstdlib>
+
+using ::webfuse_test::MockProvider;
+using ::webfuse_test::MockRequest;
+using ::webfuse_test::OpenMatcher;
+using ::webfuse_test::create_context;
+using ::testing::_;
+using ::testing::Invoke;
+using ::testing::StrEq;
+
+namespace
+{
+
+void free_request(wfp_request * request, ino_t, int)
+{
+    free(request);
+}
+
+}
+
+TEST(wfp_impl_open, invoke_provider)
+{
+    ino_t inode = 42;
+    int flags = 0;
+    MockProvider provider;
+    EXPECT_CALL(provider,open(_, inode, flags)).Times(1)
+        .WillOnce(Invoke(free_request));
+
+    wfp_request request = {nullptr, nullptr, 0};
+    wfp_impl_invokation_context context = create_context(provider, &request);
+
+    json_t * params = json_array();
+    json_array_append_new(params, json_string("test.filesystem"));
+    json_array_append_new(params, json_integer(inode));
+    json_array_append_new(params, json_integer(flags));
+
+    wfp_impl_open(&context, params, 42);
+}
+
+TEST(wfp_impl_open, fail_invalid_param_count)
+{
+    MockProvider provider;
+    EXPECT_CALL(provider,open(_, _, _)).Times(0);
+
+    wfp_request request = {nullptr, nullptr, 0};
+    wfp_impl_invokation_context context = create_context(provider, &request);
+
+    json_t * params = json_array();
+    json_array_append_new(params, json_string("test.filesystem"));
+    json_array_append_new(params, json_integer(23));
+
+    wfp_impl_open(&context, params, 42);
+}
+
+TEST(wfp_impl_open, fail_invalid_inode_type)
+{
+    MockProvider provider;
+    EXPECT_CALL(provider,open(_, _, _)).Times(0);
+
+    wfp_request request = {nullptr, nullptr, 0};
+    wfp_impl_invokation_context context = create_context(provider, &request);
+
+    json_t * params = json_array();
+    json_array_append_new(params, json_string("test.filesystem"));
+    json_array_append_new(params, json_string(""));
+    json_array_append_new(params, json_integer(0));
+
+    wfp_impl_open(&context, params, 42);
+}
+
+TEST(wfp_impl_open, fail_invalid_flags_type)
+{
+    MockProvider provider;
+    EXPECT_CALL(provider,open(_, _, _)).Times(0);
+
+    wfp_request request = {nullptr, nullptr, 0};
+    wfp_impl_invokation_context context = create_context(provider, &request);
+
+    json_t * params = json_array();
+    json_array_append_new(params, json_string("test.filesystem"));
+    json_array_append_new(params, json_integer(23));
+    json_array_append_new(params, json_string(""));
+
+    wfp_impl_open(&context, params, 42);
+}
+
+TEST(wfp_impl_open, default_responds_error)
+{
+    MockRequest request;
+    auto * req = request.create_request(42);
+    EXPECT_CALL(request, respond_error(_,42)).Times(1);
+
+    wfp_impl_open_default(req, 1, 0, nullptr);
+}
+
+TEST(wfp_impl_open, respond)
+{
+    MockRequest request;
+    auto * req = request.create_request(42);
+    EXPECT_CALL(request, respond(OpenMatcher(23), 42)).Times(1);
+
+    wfp_impl_respond_open(req, 23);
+}
+