#274 - Fix airline integration when ALE is not loaded fully

test/test_statusline_api_without_globals.vader

@@ -0,0 +1,19 @@
+" This file tests that statusline functions return meaningful output even
+" when most of ALE itself has not been loaded.
+"
+" This is important for plugins which integrate with ALE like airline.
+
+Before:
+  unlet! g:ale_buffer_info
+
+After:
+  let g:ale_buffer_info = {}
+
+Execute(ale#statusline#Update shouldn't blow up when globals are undefined):
+  call ale#statusline#Update(1, [])
+
+Execute(ale#statusline#Count should return 0 counts when globals are undefined):
+  AssertEqual [0, 0], ale#statusline#Count(1)
+
+Execute(ale#statusline#Status should return 'OK' when globals are undefined):
+  AssertEqual 'OK', ale#statusline#Status()