diff --git a/CMakeLists.txt b/CMakeLists.txt
index 11f81aae..4cf8f99a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,10 +41,10 @@ if (NOT BUILD_OPTION_DOC_ONLY)
     #---------------------------
     if (DEFINED ENV{LIBRDKAFKA_INCLUDE_DIR})
         set(LIBRDKAFKA_INCLUDE_DIR $ENV{LIBRDKAFKA_INCLUDE_DIR})
-    else ()
+    elseif (NOT DEFINED LIBRDKAFKA_INCLUDE_DIR)
         find_file(LIBRDKAFKA_HEADER
              NAMES rdkafka.h
-             HINTS /usr/include/librdkafka /usr/local/include/librdkafka /opt/homebrew/include/librdkafka)
+             HINTS /usr/include/librdkafka /usr/local/include/librdkafka /opt/homebrew/include/librdkafka /home/linuxbrew/.linuxbrew/include/librdkafka)
 
         cmake_path(GET LIBRDKAFKA_HEADER PARENT_PATH LIBRDKAFKA_INCLUDE_DIR)
         cmake_path(GET LIBRDKAFKA_INCLUDE_DIR PARENT_PATH LIBRDKAFKA_INCLUDE_DIR)
@@ -52,10 +52,10 @@ if (NOT BUILD_OPTION_DOC_ONLY)
 
     if (DEFINED ENV{LIBRDKAFKA_LIBRARY_DIR})
         set(LIBRDKAFKA_LIBRARY_DIR $ENV{LIBRDKAFKA_LIBRARY_DIR})
-    else ()
+    elseif (NOT DEFINED LIBRDKAFKA_LIBRARY_DIR)
         find_library(LIBRDKAFKA_LIB
              NAMES rdkafka
-             HINTS /usr/lib /usr/local/lib /opt/homebrew/lib)
+             HINTS /usr/lib /usr/local/lib /opt/homebrew/lib /home/linuxbrew/.linuxbrew/lib)
 
         cmake_path(GET LIBRDKAFKA_LIB PARENT_PATH LIBRDKAFKA_LIBRARY_DIR)
     endif ()
@@ -106,7 +106,7 @@ if (NOT BUILD_OPTION_DOC_ONLY)
     if (CMAKE_CXX_STANDARD EQUAL 14)
         if (DEFINED ENV{BOOST_ROOT})
             set(Boost_INCLUDE_DIRS $ENV{BOOST_ROOT}/include)
-        else ()
+        elseif (NOT DEFINED Boost_INCLUDE_DIRS)
             find_package(Boost)
             if (NOT Boost_FOUND)
                 message(FATAL_ERROR "Cound not find library: boost!")
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 4b069a6e..4de5e248 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -23,7 +23,7 @@ link_directories(${Boost_LIBRARY_DIRS})
 #---------------------------
 if (DEFINED ENV{GTEST_ROOT})
     set(GTEST_ROOT $ENV{GTEST_ROOT})
-else ()
+elseif (NOT DEFINED GTEST_ROOT)
     if (EXISTS "/usr/local/include/gtest/gtest.h")
         set(GTEST_ROOT /usr/local)
     elseif (EXISTS "/opt/homebrew/include/gtest/gtest.h")
@@ -31,20 +31,39 @@ else ()
     endif ()
 endif ()
 
-if (NOT EXISTS "${GTEST_ROOT}/include/gtest/gtest.h")
+# include dir
+if (EXISTS "${GTEST_ROOT}/include/gtest/gtest.h")
+    set(GTEST_INCLUDE_DIR ${GTEST_ROOT}/include)
+else ()
+    if (NOT DEFINED GTEST_INCLUDE_DIR)
+        set(GTEST_INCLUDE_DIR ENV{GTEST_INCLUDE_DIR})
+    endif()
+endif ()
+if (NOT DEFINED GTEST_INCLUDE_DIR)
     message(FATAL_ERROR "Could not find headers for gtest!")
+else()
+    message(STATUS "gtest include directory: ${GTEST_INCLUDE_DIR}")
 endif ()
 
-if (NOT (EXISTS "${GTEST_ROOT}/lib/libgtest_main.a"
+if ((EXISTS "${GTEST_ROOT}/lib/libgtest_main.a"
          OR EXISTS "${GTEST_ROOT}/lib/libgtest_main.so"
          OR EXISTS "${GTEST_ROOT}/lib/gtest_main.lib"))
+         set(GTEST_LIBRARY_DIR ${GTEST_ROOT}/lib)
+else ()
+    if (NOT DEFINED GTEST_LIBRARY_DIR)
+        set(GTEST_LIBRARY_DIR ENV{GTEST_LIBRARY_DIR})
+    endif()
+endif ()
+if (NOT DEFINED GTEST_LIBRARY_DIR)
     message(FATAL_ERROR "Could not find library for gtest!")
+else()
+    message(STATUS "gtest library directory: ${GTEST_LIBRARY_DIR}")
 endif ()
 
 message(STATUS "googletest root directory: ${GTEST_ROOT}")
 
-include_directories(SYSTEM ${GTEST_ROOT}/include)
-link_directories(${GTEST_ROOT}/lib ${GTEST_ROOT}/bin)
+include_directories(SYSTEM ${GTEST_INCLUDE_DIR})
+link_directories(${GTEST_LIBRARY_DIR} ${GTEST_ROOT}/bin)
 
 
 #---------------------------
diff --git a/tests/unit/CMakeLists.txt b/tests/unit/CMakeLists.txt
index e4c8a0a7..09744d21 100644
--- a/tests/unit/CMakeLists.txt
+++ b/tests/unit/CMakeLists.txt
@@ -5,7 +5,7 @@ project("kafka-unit-test")
 #---------------------------
 if (DEFINED ENV{RAPIDJSON_INCLUDE_DIRS})
     set(RAPIDJSON_INCLUDE_DIRS $ENV{RAPIDJSON_INCLUDE_DIRS})
-else ()
+elseif (NOT DEFINED RAPIDJSON_INCLUDE_DIRS)
     find_file(RAPIDJSON_HEADER
         NAMES rapidjson.h
         HINTS /usr/include/rapidjson /usr/local/include/rapidjson /opt/homebrew/include/rapidjson)