tests: move .cache to build, rename test/_utils.vim

test/_utils.vim

@@ -0,0 +1,11 @@
+function! CurrentBufferIsModule(module_name)
+    return EndsWith(bufname('%'), a:module_name.'.py')
+endfunction
+
+
+function EndsWith(string, end)
+    let l:should = len(a:string) - strlen(a:end)
+    return l:should == stridx(a:string, a:end, should)
+endfunction
+
+" vim: et:ts=4:sw=4