--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -308,6 +308,9 @@
 
 include(CTest)
 
+# Approval tests require python 2.7 or 3
+find_package(PythonInterp)
+
 if (BUILD_TESTING AND NOT_SUBPROJECT)
     add_executable(SelfTest ${TEST_SOURCES} ${IMPL_SOURCES} ${REPORTER_SOURCES} ${SURROGATE_SOURCES} ${HEADERS})
     target_include_directories(SelfTest PRIVATE ${HEADER_DIR})
@@ -384,7 +387,11 @@
     set_tests_properties(NoTest PROPERTIES PASS_REGULAR_EXPRESSION "No test cases matched")
 
     # AppVeyor has a Python 2.7 in path, but doesn't have .py files as autorunnable
-    add_test(NAME ApprovalTests COMMAND python ${CMAKE_CURRENT_SOURCE_DIR}/scripts/approvalTests.py $<TARGET_FILE:SelfTest>)
+    if(NOT ${PYTHONINTERP_FOUND})
+        message(FATAL_ERROR "Python not found, but required for running tests!")
+    endif()
+
+    add_test(NAME ApprovalTests COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/scripts/approvalTests.py $<TARGET_FILE:SelfTest>)
     set_tests_properties(ApprovalTests PROPERTIES FAIL_REGULAR_EXPRESSION "Results differed")
 
     if (CATCH_USE_VALGRIND)