Make the test C import path test fail less

autoload/ale/c.vim

@@ -4,8 +4,11 @@
 call ale#Set('c_parse_makefile', 0)
 let s:sep = has('win32') ? '\' : '/'
 
+" Set just so tests can override it.
+let g:__ale_c_project_filenames = ['.git/HEAD', 'configure', 'Makefile', 'CMakeLists.txt']
+
 function! ale#c#FindProjectRoot(buffer) abort
-    for l:project_filename in ['.git/HEAD', 'configure', 'Makefile', 'CMakeLists.txt']
+    for l:project_filename in g:__ale_c_project_filenames
         let l:full_path = ale#path#FindNearestFile(a:buffer, l:project_filename)
 
         if !empty(l:full_path)

test/test_c_import_paths.vader

@@ -1,8 +1,21 @@
 Before:
+  " Make sure the c.vim file is loaded first.
+  call ale#c#FindProjectRoot(bufnr(''))
+
   Save g:ale_c_gcc_options
   Save g:ale_c_clang_options
   Save g:ale_cpp_gcc_options
   Save g:ale_cpp_clang_options
+  Save g:__ale_c_project_filenames
+
+  let g:original_project_filenames = g:__ale_c_project_filenames
+
+  " Remove the .git/HEAD dir for C import paths for these tests.
+  " The tests run inside of a git repo.
+  let g:__ale_c_project_filenames = filter(
+  \ copy(g:__ale_c_project_filenames),
+  \ 'v:val isnot# ''.git/HEAD'''
+  \)
 
   call ale#test#SetDirectory('/testplugin/test')
 
@@ -14,23 +27,11 @@ Before:
 After:
   Restore
 
+  unlet! g:original_project_filenames
+
   call ale#test#RestoreDirectory()
   call ale#linter#Reset()
 
-" Run this only once for this series of tests. The cleanup Execute step
-" will run at the bottom of this file.
-"
-" We need to move .git/HEAD away so we don't match it, as we need to test
-" functions which look for .git/HEAD.
-Execute(Move .git/HEAD to a temp dir):
-  let g:temp_head_filename = tempname()
-  let g:head_filename = findfile('.git/HEAD', ';')
-
-  if !empty(g:head_filename)
-    call writefile(readfile(g:head_filename, 'b'), g:temp_head_filename, 'b')
-    call delete(g:head_filename)
-  endif
-
 Execute(The C GCC handler should include 'include' directories for projects with a Makefile):
   runtime! ale_linters/c/gcc.vim
 
@@ -242,13 +243,8 @@ Execute(The C++ Clang handler should include root directories for projects with
 Execute(The C++ Clang handler shoud use the include directory based on the .git location):
   runtime! ale_linters/cpp/clang.vim
 
-  if !isdirectory(g:dir . '/test_c_projects/git_and_nested_makefiles/.git')
+  " Restore the .git/HEAD check for just this test.
-    call mkdir(g:dir . '/test_c_projects/git_and_nested_makefiles/.git')
+  let g:__ale_c_project_filenames = g:original_project_filenames
-  endif
-
-  if !filereadable(g:dir . '/test_c_projects/git_and_nested_makefiles/.git/HEAD')
-    call writefile([], g:dir . '/test_c_projects/git_and_nested_makefiles/.git/HEAD')
-  endif
 
   call ale#test#SetFilename('test_c_projects/git_and_nested_makefiles/src/file.cpp')
 
@@ -270,12 +266,3 @@ Execute(The C++ ClangTidy handler should include json folders for projects with
   \   . ' -checks=' . ale#Escape('*') . ' %s '
   \   . '-p ' . ale#Escape(ale#path#Simplify(g:dir . '/test_c_projects/json_project/build'))
   \ , ale_linters#cpp#clangtidy#GetCommand(bufnr(''))
-
-Execute(Move .git/HEAD back):
-  if !empty(g:head_filename)
-    call writefile(readfile(g:temp_head_filename, 'b'), g:head_filename, 'b')
-    call delete(g:temp_head_filename)
-  endif
-
-  unlet! g:temp_head_filename
-  unlet! g:head_filename