Rename tests/Unit to tests/unit

This is more uniform with the directory structure we have in revng

tests/Tests.cmake

@@ -5,4 +5,4 @@
 enable_testing()
 
 # Give control to the various subdirectories
-include(${CMAKE_SOURCE_DIR}/tests/Unit/UnitTests.cmake)
+include(${CMAKE_SOURCE_DIR}/tests/unit/UnitTests.cmake)

tests/Unit/llvm-lit-tests/CMakeLists.txt

@@ -1,6 +0,0 @@
-configure_file(
-  ${CMAKE_SOURCE_DIR}/tests/Unit/llvm-lit-tests/lit.site.cfg.py.in
-  ${CMAKE_BINARY_DIR}/tests/Unit/llvm-lit-tests/lit.site.cfg.py @ONLY)
-
-add_test(NAME llvm-lit-tests
-         COMMAND lit -a ${CMAKE_BINARY_DIR}/tests/Unit/llvm-lit-tests/)

tests/unit/UnitTests.cmake

@@ -6,7 +6,7 @@ cmake_policy(SET CMP0060 NEW)
 
 include(${CMAKE_INSTALL_PREFIX}/share/revng/qa/cmake/revng-qa.cmake)
 
-set(SRC "${CMAKE_SOURCE_DIR}/tests/Unit")
+set(SRC "${CMAKE_SOURCE_DIR}/tests/unit")
 
 include(${SRC}/llvm-lit-tests/CMakeLists.txt)
 

tests/unit/llvm-lit-tests/CMakeLists.txt

@@ -0,0 +1,6 @@
+configure_file(
+  ${CMAKE_SOURCE_DIR}/tests/unit/llvm-lit-tests/lit.site.cfg.py.in
+  ${CMAKE_BINARY_DIR}/tests/unit/llvm-lit-tests/lit.site.cfg.py @ONLY)
+
+add_test(NAME llvm-lit-tests
+         COMMAND lit -a ${CMAKE_BINARY_DIR}/tests/unit/llvm-lit-tests/)

tests/unit/llvm-lit-tests/lit.site.cfg.py.in

@@ -7,4 +7,4 @@ import os
 config.my_src_root=r'@CMAKE_SOURCE_DIR@'
 config.my_obj_root=r'@CMAKE_BINARY_DIR@'
 lit_config.load_config(config, os.path.join(config.my_src_root,
-                                            'tests/Unit/llvm-lit-tests/lit.cfg.py'))
+                                            'tests/unit/llvm-lit-tests/lit.cfg.py'))