Add an AssertLinter command for tests

autoload/ale/assert.vim

@@ -0,0 +1,50 @@
+function! s:GetLinter() abort
+    let l:linters = ale#linter#GetLintersLoaded()
+    let l:filetype_linters = get(values(l:linters), 0, [])
+
+    if len(l:linters) is 0 || len(l:filetype_linters) is 0
+        throw 'No linters were loaded'
+    endif
+
+    if len(l:linters) > 1 || len(l:filetype_linters) > 1
+        throw 'More than one linter was loaded'
+    endif
+
+    return l:filetype_linters[0]
+endfunction
+
+" Load the currently loaded linter for a test case, and check that the command
+" matches the given string.
+function! ale#assert#Linter(expected_executable, expected_command) abort
+    let l:buffer = bufnr('')
+    let l:linter = s:GetLinter()
+    let l:executable = ale#linter#GetExecutable(l:buffer, l:linter)
+
+    if has_key(l:linter, 'command_chain')
+        let l:command = []
+
+        for l:chain_item in l:linter.command_chain
+            if empty(l:command)
+                call add(l:command, call(l:chain_item.callback, [l:buffer]))
+            else
+                call add(l:command, call(l:chain_item.callback, [l:buffer, []]))
+            endif
+        endfor
+    else
+        let l:command = ale#linter#GetCommand(l:buffer, l:linter)
+        " Replace %e with the escaped executable, so tests keep passing after
+        " linters are changed to use %e.
+        let l:command = substitute(l:command, '%e', '\=ale#Escape(l:executable)', 'g')
+    endif
+
+    AssertEqual
+    \   [a:expected_executable, a:expected_command],
+    \   [l:executable, l:command]
+endfunction
+
+command! -nargs=+ AssertLinter :call ale#assert#Linter(<args>)
+
+" A dummy function for making sure this module is loaded.
+function! ale#assert#Init() abort
+    call ale#linter#Reset()
+endfunction

autoload/ale/linter.vim

@@ -47,6 +47,13 @@ function! ale#linter#Reset() abort
     let s:linters = {}
 endfunction
 
+" Return a reference to the linters loaded.
+" This is only for tests.
+" Do not call this function.
+function! ale#linter#GetLintersLoaded() abort
+    return s:linters
+endfunction
+
 function! s:IsCallback(value) abort
     return type(a:value) == type('') || type(a:value) == type(function('type'))
 endfunction

test/command_callback/test_tslint_command_callback.vader

@@ -1,4 +1,6 @@
 Before:
+  call ale#assert#Init()
+
   Save g:ale_typescript_tslint_executable
   Save g:ale_typescript_tslint_config_path
   Save g:ale_typescript_tslint_rules_dir
@@ -26,26 +28,25 @@ After:
   call ale#linter#Reset()
 
 Execute(The default tslint command should be correct):
-  AssertEqual
+  AssertLinter
+  \ 'tslint',
   \ 'cd ' . ale#Escape(expand('%:p:h')) . ' && '
-  \   . ale#Escape('tslint') . ' --format json %t',
-  \ ale_linters#typescript#tslint#GetCommand(bufnr(''))
+  \   . ale#Escape('tslint') . ' --format json %t'
 
 Execute(The rules directory option should be included if set):
   let b:ale_typescript_tslint_rules_dir = '/foo/bar'
 
-  AssertEqual
+  AssertLinter
+  \ 'tslint',
   \ 'cd ' . ale#Escape(expand('%:p:h')) . ' && '
   \   . ale#Escape('tslint') . ' --format json'
   \   . ' -r ' . ale#Escape('/foo/bar')
-  \   . ' %t',
-  \ ale_linters#typescript#tslint#GetCommand(bufnr(''))
+  \   . ' %t'
 
 Execute(The executable should be configurable and escaped):
   let b:ale_typescript_tslint_executable = 'foo bar'
 
-  AssertEqual 'foo bar', ale_linters#typescript#tslint#GetExecutable(bufnr(''))
-  AssertEqual
+  AssertLinter
+  \ 'foo bar',
   \ 'cd ' . ale#Escape(expand('%:p:h')) . ' && '
-  \   . ale#Escape('foo bar') . ' --format json %t',
-  \ ale_linters#typescript#tslint#GetCommand(bufnr(''))
+  \   . ale#Escape('foo bar') . ' --format json %t'

test/command_callback/test_write_good_command_callback.vader

@@ -1,4 +1,6 @@
 Before:
+  call ale#assert#Init()
+
   Save g:ale_writegood_options
   Save g:ale_writegood_executable
   Save g:ale_writegood_use_global
@@ -7,6 +9,8 @@ Before:
   unlet! g:ale_writegood_executable
   unlet! g:ale_writegood_use_global
 
+  runtime ale_linters/markdown/write-good.vim
+
   call ale#test#SetDirectory('/testplugin/test/command_callback')
   call ale#test#SetFilename('testfile.txt')
 
@@ -16,42 +20,36 @@ After:
   Restore
 
   call ale#test#RestoreDirectory()
+  call ale#linter#Reset()
 
 Execute(The global executable should be used when the local one cannot be found):
-  AssertEqual 'write-good', ale#handlers#writegood#GetExecutable(bufnr(''))
-  AssertEqual
+  AssertLinter
+  \ 'write-good',
   \ ale#Escape('write-good') . ' %t',
-  \ ale#handlers#writegood#GetCommand(bufnr(''))
 
 Execute(The options should be used in the command):
   let g:ale_writegood_options = '--foo --bar'
 
-  AssertEqual
+  AssertLinter
+  \ 'write-good',
   \ ale#Escape('write-good') . ' --foo --bar %t',
-  \ ale#handlers#writegood#GetCommand(bufnr(''))
 
 Execute(Should use the node_modules/.bin executable, if available):
   call ale#test#SetFilename('write-good-node-modules/test.txt')
 
-  AssertEqual
+  AssertLinter
   \ ale#path#Simplify(g:dir . '/write-good-node-modules/node_modules/.bin/write-good'),
-  \ ale#handlers#writegood#GetExecutable(bufnr(''))
-  AssertEqual
   \ ale#Escape(ale#path#Simplify(g:dir . '/write-good-node-modules/node_modules/.bin/write-good'))
   \   . ' %t',
-  \ ale#handlers#writegood#GetCommand(bufnr(''))
 
 Execute(Should use the node_modules/write-good executable, if available):
   call ale#test#SetFilename('write-good-node-modules-2/test.txt')
 
-  AssertEqual
+  AssertLinter
   \ ale#path#Simplify(g:dir . '/write-good-node-modules-2/node_modules/write-good/bin/write-good.js'),
-  \ ale#handlers#writegood#GetExecutable(bufnr(''))
-  AssertEqual
   \   (has('win32') ? 'node.exe ' : '')
   \   . ale#Escape(ale#path#Simplify(g:dir . '/write-good-node-modules-2/node_modules/write-good/bin/write-good.js'))
   \   . ' %t',
-  \ ale#handlers#writegood#GetCommand(bufnr(''))
 
 Execute(Should let users configure a global executable and override local paths):
   call ale#test#SetFilename('write-good-node-modules-2/test.txt')
@@ -59,7 +57,4 @@ Execute(Should let users configure a global executable and override local paths)
   let g:ale_writegood_executable = 'foo-bar'
   let g:ale_writegood_use_global = 1
 
-  AssertEqual 'foo-bar', ale#handlers#writegood#GetExecutable(bufnr(''))
-  AssertEqual
-  \ ale#Escape('foo-bar') . ' %t',
-  \ ale#handlers#writegood#GetCommand(bufnr(''))
+  AssertLinter 'foo-bar', ale#Escape('foo-bar') . ' %t'