ignore tests in report

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d7c8796..3796c45 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -199,7 +199,7 @@
     if (BUILD_TESTS)
         if (COVERAGE)
             APPEND_COVERAGE_COMPILER_FLAGS()
-            set(COVERAGE_LCOV_EXCLUDES '/usr/include/*' '3rdparty/*' 'generated/*' 'bba/*')
+            set(COVERAGE_LCOV_EXCLUDES '/usr/include/*' '3rdparty/*' 'generated/*' 'bba/*' 'tests/*')
             SETUP_TARGET_FOR_COVERAGE_LCOV(
                 NAME ${family}-coverage 
                 EXECUTABLE nextpnr-${family}-test