Cover basic GCC functionality with tests

test/c_tests/test_gcc.vader

@@ -0,0 +1,63 @@
+Before:
+  Save g:ale_run_synchronously
+  Save g:ale_linters
+  Save g:ale_history_log_output
+  Save g:ale_cpp_gcc_options
+
+  silent! cd /testplugin/test/c_tests
+
+  let g:ale_run_synchronously = 1
+  let g:ale_linters = {'c': ['gcc'], 'cpp': ['g++']}
+  let g:ale_history_log_output = 1
+  let g:ale_cpp_gcc_options = '-Wall'
+
+  function! GetCommandOutput()
+    if empty(g:ale_buffer_info[bufnr('')].history)
+      return ''
+    endif
+
+    return join(g:ale_buffer_info[bufnr('')].history[-1].output, "\n")
+  endfunction
+
+After:
+  Restore
+  delfunction GetCommandOutput
+  call ale#linter#Reset()
+  call ale#engine#SetResults(bufnr(''), [])
+  call ale#cleanup#Buffer(bufnr(''))
+
+Given c (A test C file):
+  int main() {
+    return 0
+  }
+
+Execute(Basic errors should be returned for GCC for C files):
+  call ale#Lint()
+
+  AssertEqual [{
+  \   'lnum': 3,
+  \   'col': 1,
+  \ }],
+  \ map(getloclist(0), '{''lnum'': v:val.lnum, ''col'': v:val.col}'),
+  \ 'No errors returned! Got: ' . GetCommandOutput()
+
+  Assert match(getloclist(0)[0].text, '\v^expected .*;.* before .*\}.* token$') >= 0,
+  \ 'Invalid error text: ' .  getloclist(0)[0].text
+
+Given cpp (A test C++ file):
+  int main() {
+    return 0
+  }
+
+Execute(Basic errors should be returned for GCC for C++ files):
+  call ale#Lint()
+
+  AssertEqual [{
+  \   'lnum': 3,
+  \   'col': 1,
+  \ }],
+  \ map(getloclist(0), '{''lnum'': v:val.lnum, ''col'': v:val.col}'),
+  \ 'No errors returned! Got: ' . GetCommandOutput()
+
+  Assert match(getloclist(0)[0].text, '\v^expected .*;.* before .*\}.* token$') >= 0,
+  \ 'Invalid error text: ' .  getloclist(0)[0].text

test/vimrc

@@ -8,6 +8,7 @@ set runtimepath=/home/vim,$VIM/vimfiles,$VIMRUNTIME,$VIM/vimfiles/after,/testplu
 filetype plugin indent on
 syntax on
 set shell=/bin/sh
+set shellcmdflag=-c
 set nocompatible
 set tabstop=4
 set softtabstop=4