diff --git a/unitTests/CMakeLists.txt b/unitTests/CMakeLists.txt
index f4340834..55104533 100644
--- a/unitTests/CMakeLists.txt
+++ b/unitTests/CMakeLists.txt
@@ -19,23 +19,28 @@ endforeach()
 
 add_executable(unit_tests mainTestRunner.cpp
     gtestwrapper.h
-    test_basicio.cpp
-    test_types.cpp
-    test_tiffheader.cpp
-    test_futils.cpp
-    test_enforce.cpp
-    test_safe_op.cpp
-    test_XmpKey.cpp
     test_DateValue.cpp
     test_TimeValue.cpp
+    test_XmpKey.cpp
+    test_basicio.cpp
     test_cr2header_int.cpp
+    test_enforce.cpp
+    test_FileIo.cpp
+    test_futils.cpp
     test_helper_functions.cpp
-    test_slice.cpp
     test_image_int.cpp
+    test_safe_op.cpp
+    test_slice.cpp
+    test_tiffheader.cpp
+    test_types.cpp
     ${unit_tests_exiv2lib_SOURCES}
 )
 
-target_compile_definitions(unit_tests PRIVATE exiv2lib_STATIC)
+target_compile_definitions(unit_tests
+  PRIVATE
+    exiv2lib_STATIC
+    TESTDATA_PATH="${PROJECT_SOURCE_DIR}/test/data"
+)
 
 if (exiv2lib_COMPILE_DEFINITIONS)
     target_compile_definitions(unit_tests PRIVATE ${exiv2lib_COMPILE_DEFINITIONS})
diff --git a/unitTests/test_FileIo.cpp b/unitTests/test_FileIo.cpp
new file mode 100644
index 00000000..1cfbda11
--- /dev/null
+++ b/unitTests/test_FileIo.cpp
@@ -0,0 +1,74 @@
+#include "basicio.hpp"
+
+#include <gtest/gtest.h>
+
+using namespace Exiv2;
+
+namespace
+{
+    const std::string testData(TESTDATA_PATH);
+    const std::string imagePath(testData + "/DSC_3079.jpg");
+}  // namespace
+
+TEST(AFileIO, canBeInstantiatedWithFilePath)
+{
+    ASSERT_NO_THROW(FileIo file(imagePath));
+}
+
+TEST(AFileIO, canBeOpenInReadBinaryMode)
+{
+    FileIo file(imagePath);
+    ASSERT_EQ(0, file.open());
+}
+
+TEST(AFileIO, isOpenDoItsJob)
+{
+    FileIo file(imagePath);
+    ASSERT_FALSE(file.isopen());
+    file.open();
+    ASSERT_TRUE(file.isopen());
+}
+
+TEST(AFileIO, returnsFileSizeIfItsOpened)
+{
+    FileIo file(imagePath);
+    file.open();
+    ASSERT_EQ(118685, file.size());
+}
+
+TEST(AFileIO, returnsFileSizeEvenWhenFileItIsNotOpened)
+{
+    FileIo file(imagePath);
+    ASSERT_EQ(118685, file.size());
+}
+
+TEST(AFileIO, isOpenedAtPosition0)
+{
+    FileIo file(imagePath);
+    file.open();
+    ASSERT_EQ(0, file.tell());
+}
+
+TEST(AFileIO, canSeekToExistingPositions)
+{
+    FileIo file(imagePath);
+    file.open();
+
+    ASSERT_EQ(0, file.seek(100, BasicIo::beg));
+    ASSERT_EQ(0, file.seek(-50, BasicIo::cur));
+    ASSERT_EQ(0, file.seek(-50, BasicIo::end));
+
+    ASSERT_FALSE(file.error());
+    ASSERT_FALSE(file.eof());
+}
+
+TEST(AFileIO, canSeekBeyondEOF)
+{
+    FileIo file(imagePath);
+    file.open();
+
+    // POSIX allows seeking beyond the existing end of file.
+    ASSERT_EQ(0, file.seek(200000, BasicIo::beg));
+    ASSERT_FALSE(file.error());
+    ASSERT_FALSE(file.eof());
+}