diff --git a/test/manager_write_unittest.cpp b/test/manager_write_unittest.cpp
new file mode 100644
index 0000000..33c6d5a
--- /dev/null
+++ b/test/manager_write_unittest.cpp
@@ -0,0 +1,90 @@
+#include "blob_mock.hpp"
+#include "manager.hpp"
+
+#include <gtest/gtest.h>
+
+using ::testing::_;
+using ::testing::Return;
+
+namespace blobs
+{
+
+TEST(ManagerWriteTest, WriteNoSessionReturnsFalse)
+{
+    // Calling Write on a session that doesn't exist should return false.
+
+    BlobManager mgr;
+    uint16_t sess = 1;
+    uint32_t ofs = 0x54;
+    std::vector<uint8_t> data = {0x11, 0x22};
+
+    EXPECT_FALSE(mgr.write(sess, ofs, data));
+}
+
+TEST(ManagerWriteTest, WriteSessionFoundButHandlerReturnsFalse)
+{
+    // The handler was found but it returned failure.
+
+    BlobManager mgr;
+    std::unique_ptr<BlobMock> m1 = std::make_unique<BlobMock>();
+    auto m1ptr = m1.get();
+    EXPECT_TRUE(mgr.registerHandler(std::move(m1)));
+
+    uint16_t flags = OpenFlags::write, sess;
+    std::string path = "/asdf/asdf";
+    uint32_t ofs = 0x54;
+    std::vector<uint8_t> data = {0x11, 0x22};
+
+    EXPECT_CALL(*m1ptr, canHandleBlob(path)).WillOnce(Return(true));
+    EXPECT_CALL(*m1ptr, open(_, flags, path)).WillOnce(Return(true));
+    EXPECT_TRUE(mgr.open(flags, path, &sess));
+
+    EXPECT_CALL(*m1ptr, write(sess, ofs, data)).WillOnce(Return(false));
+
+    EXPECT_FALSE(mgr.write(sess, ofs, data));
+}
+
+TEST(ManagerWriteTest, WriteFailsBecauseFileOpenedReadOnly)
+{
+    // The manager will not route a write call to a file opened read-only.
+
+    BlobManager mgr;
+    std::unique_ptr<BlobMock> m1 = std::make_unique<BlobMock>();
+    auto m1ptr = m1.get();
+    EXPECT_TRUE(mgr.registerHandler(std::move(m1)));
+
+    uint16_t flags = OpenFlags::read, sess;
+    std::string path = "/asdf/asdf";
+    uint32_t ofs = 0x54;
+    std::vector<uint8_t> data = {0x11, 0x22};
+
+    EXPECT_CALL(*m1ptr, canHandleBlob(path)).WillOnce(Return(true));
+    EXPECT_CALL(*m1ptr, open(_, flags, path)).WillOnce(Return(true));
+    EXPECT_TRUE(mgr.open(flags, path, &sess));
+
+    EXPECT_FALSE(mgr.write(sess, ofs, data));
+}
+
+TEST(ManagerWriteTest, WriteSessionFoundAndHandlerReturnsSuccess)
+{
+    // The handler was found and returned success.
+
+    BlobManager mgr;
+    std::unique_ptr<BlobMock> m1 = std::make_unique<BlobMock>();
+    auto m1ptr = m1.get();
+    EXPECT_TRUE(mgr.registerHandler(std::move(m1)));
+
+    uint16_t flags = OpenFlags::write, sess;
+    std::string path = "/asdf/asdf";
+    uint32_t ofs = 0x54;
+    std::vector<uint8_t> data = {0x11, 0x22};
+
+    EXPECT_CALL(*m1ptr, canHandleBlob(path)).WillOnce(Return(true));
+    EXPECT_CALL(*m1ptr, open(_, flags, path)).WillOnce(Return(true));
+    EXPECT_TRUE(mgr.open(flags, path, &sess));
+
+    EXPECT_CALL(*m1ptr, write(sess, ofs, data)).WillOnce(Return(true));
+
+    EXPECT_TRUE(mgr.write(sess, ofs, data));
+}
+} // namespace blobs