diff --git a/CMakeLists.txt b/CMakeLists.txt
index 77cf69d..780c940 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,6 +34,12 @@ if(WITH_CLANG-TIDY)
     "-quiet")
 endif()
 
+# Dependencies.
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(cgicc REQUIRED IMPORTED_TARGET cgicc)
+find_package(nlohmann_json REQUIRED CONFIG)
+find_package(Filesystem REQUIRED COMPONENTS Final Experimental)
+
 add_subdirectory(src)
 
 if(WITH_TESTS)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c66aaf2..a4f8958 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,10 +1,5 @@
 include(GNUInstallDirs)
 
-find_package(PkgConfig REQUIRED)
-pkg_check_modules(cgicc REQUIRED IMPORTED_TARGET cgicc)
-find_package(nlohmann_json REQUIRED CONFIG)
-find_package(Filesystem REQUIRED COMPONENTS Final Experimental)
-
 configure_file(fs-compat.hpp.in fs-compat.hpp @ONLY)
 
 add_executable(${PROJECT_NAME} main.cpp)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 8261b1c..2730a64 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,5 +1,16 @@
 include(CTest)
 
+file(GLOB sources_testlib ../src/*.cpp)
+add_library(${PROJECT_NAME}_testlib SHARED ${sources_testlib})
+
+target_include_directories(${PROJECT_NAME}_testlib
+  PUBLIC
+  "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>"
+  "$<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/src>")
+
+target_link_libraries(${PROJECT_NAME}_testlib
+  PUBLIC PkgConfig::cgicc nlohmann_json std::filesystem)
+
 file(GLOB sources_tests test_*.cpp)
 
 find_package(Catch2 CONFIG)
@@ -8,7 +19,7 @@ if(Catch2_FOUND)                # Catch 2.x
   include(Catch)
   add_executable(all_tests main.cpp ${sources_tests})
   target_link_libraries(all_tests
-    PRIVATE Catch2::Catch2)
+    PRIVATE Catch2::Catch2 ${PROJECT_NAME}_testlib)
   target_include_directories(all_tests PRIVATE "/usr/include/catch2")
   catch_discover_tests(all_tests EXTRA_ARGS "${EXTRA_TEST_ARGS}")
 else()                          # Catch 1.x
@@ -17,6 +28,7 @@ else()                          # Catch 1.x
     foreach(src ${sources_tests})
       get_filename_component(bin ${src} NAME_WE)
       add_executable(${bin} main.cpp ${src})
+      target_link_libraries(${bin} PRIVATE ${PROJECT_NAME}_testlib)
       add_test(${bin} ${bin} "${EXTRA_TEST_ARGS}")
     endforeach()
   else()
diff --git a/tests/main.cpp b/tests/main.cpp
index b70e7ab..e48147e 100644
--- a/tests/main.cpp
+++ b/tests/main.cpp
@@ -1,19 +1,3 @@
-/*  This file is part of FediBlock-backend.
- *  Copyright © 2020 tastytea <tastytea@tastytea.de>
- *
- *  This program is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU Affero General Public License as published by
- *  the Free Software Foundation, version 3.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU Affero General Public License for more details.
- *
- *  You should have received a copy of the GNU Affero General Public License
- *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
 #define CATCH_CONFIG_MAIN
 
 #include <catch.hpp>
diff --git a/tests/test_string_to_vector.cpp b/tests/test_string_to_vector.cpp
new file mode 100644
index 0000000..803c6d5
--- /dev/null
+++ b/tests/test_string_to_vector.cpp
@@ -0,0 +1,131 @@
+#include "cgi.cpp"
+
+#include <catch.hpp>
+
+#include <exception>
+#include <string>
+#include <vector>
+
+namespace FediBlock
+{
+
+using std::string;
+using std::vector;
+
+SCENARIO("string_to_vector()")
+{
+    bool exception{false};
+    vector<string> vec;
+
+    {
+        const string str{"a,b,c,d"};
+        WHEN("string is " + str)
+        {
+            try
+            {
+                vec = string_to_vector(str);
+            }
+            catch (std::exception &)
+            {
+                exception = true;
+            }
+
+            THEN("No exception is thrown")
+            AND_THEN(R"(vector is {"a", "b", "c", "d"})")
+            {
+                REQUIRE_FALSE(exception);
+                REQUIRE(vec == vector<string>({"a", "b", "c", "d"}));
+            }
+        }
+    }
+
+    {
+        const string str{""};
+        WHEN("string is \"" + str + '"')
+        {
+            try
+            {
+                vec = string_to_vector(str);
+            }
+            catch (std::exception &)
+            {
+                exception = true;
+            }
+
+            THEN("No exception is thrown")
+            AND_THEN(R"(vector is {})")
+            {
+                REQUIRE_FALSE(exception);
+                REQUIRE(vec == vector<string>());
+            }
+        }
+    }
+
+    {
+        const string str{"a,b,"};
+        WHEN("string is \"" + str + '"')
+        {
+            try
+            {
+                vec = string_to_vector(str);
+            }
+            catch (std::exception &)
+            {
+                exception = true;
+            }
+
+            THEN("No exception is thrown")
+            AND_THEN(R"(vector is {"a", "b"})")
+            {
+                REQUIRE_FALSE(exception);
+                REQUIRE(vec == vector<string>({"a", "b"}));
+            }
+        }
+    }
+
+    {
+        const string str{",a,b"};
+        WHEN("string is \"" + str + '"')
+        {
+            try
+            {
+                vec = string_to_vector(str);
+            }
+            catch (std::exception &)
+            {
+                exception = true;
+            }
+
+            THEN("No exception is thrown")
+            AND_THEN(R"(vector is {"a", "b"})")
+            {
+                REQUIRE_FALSE(exception);
+                REQUIRE(vec == vector<string>({"a", "b"}));
+            }
+        }
+    }
+
+    {
+        const string str{",,,"};
+        WHEN("string is \"" + str + '"')
+        {
+            try
+            {
+                vec = string_to_vector(str);
+            }
+            catch (std::exception &)
+            {
+                exception = true;
+            }
+
+            THEN("No exception is thrown")
+            AND_THEN(R"(vector is {})")
+            {
+                REQUIRE_FALSE(exception);
+                REQUIRE(vec == vector<string>());
+            }
+        }
+    }
+}
+
+} // namespace FediBlock