#392 - Detect and use compile_commands.json for cppcheck

test/command_callback/test_cppcheck_command_callbacks.vader

@@ -0,0 +1,40 @@
+Before:
+  silent! cd /testplugin/test/command_callback
+  let b:dir = getcwd()
+
+After:
+  silent execute 'cd ' . fnameescape(b:dir)
+  unlet! b:dir
+  call ale#linter#Reset()
+
+Execute(The default C cppcheck command should be correct):
+  runtime ale_linters/c/cppcheck.vim
+
+  AssertEqual
+  \ 'cppcheck -q --language=c --enable=style %t',
+  \ ale_linters#c#cppcheck#GetCommand(bufnr(''))
+
+Execute(cppcheck for C should detect compile_commands.json files):
+  runtime ale_linters/c/cppcheck.vim
+  cd cppcheck_paths/one
+
+  AssertEqual
+  \ 'cd ' . fnameescape(b:dir . '/cppcheck_paths/one') . ' && '
+  \ . 'cppcheck -q --language=c --project=compile_commands.json --enable=style %t',
+  \ ale_linters#c#cppcheck#GetCommand(bufnr(''))
+
+Execute(The default C++ cppcheck command should be correct):
+  runtime ale_linters/cpp/cppcheck.vim
+
+  AssertEqual
+  \ 'cppcheck -q --language=c++ --enable=style %t',
+  \ ale_linters#cpp#cppcheck#GetCommand(bufnr(''))
+
+Execute(cppcheck for C++ should detect compile_commands.json files):
+  runtime ale_linters/cpp/cppcheck.vim
+  cd cppcheck_paths/one
+
+  AssertEqual
+  \ 'cd ' . fnameescape(b:dir . '/cppcheck_paths/one') . ' && '
+  \ . 'cppcheck -q --language=c++ --project=compile_commands.json --enable=style %t',
+  \ ale_linters#cpp#cppcheck#GetCommand(bufnr(''))