Add auto-fixer for crystal (#4016)

autoload/ale/fix/registry.vim

@@ -431,6 +431,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['hcl', 'terraform'],
 \       'description': 'Fix tf and hcl files with terraform fmt.',
 \   },
+\   'crystal': {
+\       'function': 'ale#fixers#crystal#Fix',
+\       'suggested_filetypes': ['cr'],
+\       'description': 'Fix cr (crystal).',
+\   },
 \   'ktlint': {
 \       'function': 'ale#fixers#ktlint#Fix',
 \       'suggested_filetypes': ['kt', 'kotlin'],

autoload/ale/fixers/crystal.vim

@@ -0,0 +1,14 @@
+call ale#Set('crystal_format_executable', 'crystal')
+call ale#Set('crystal_format_options', '')
+
+function! ale#fixers#crystal#Fix(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'crystal_format_executable')
+    let l:options = ale#Var(a:buffer, 'crystal_format_options')
+
+    return {
+    \   'command': ale#Escape(l:executable)
+    \       . ' tool format'
+    \       . ale#Pad(l:options)
+    \       . ' -'
+    \}
+endfunction

test/fixers/test_crystal_format_fixer_callback.vader

@@ -0,0 +1,33 @@
+Before:
+  Save g:ale_crystal_format_executable
+  Save g:ale_crystal_format_options
+
+  " Use an invalid global executable, so we don't match it.
+  let g:ale_crystal_format_executable = 'xxxinvalid'
+  let g:ale_crystal_format_options = ''
+
+  call ale#test#SetDirectory('/testplugin/test/fixers')
+
+After:
+  Restore
+
+  call ale#test#RestoreDirectory()
+
+Execute(The crystal format callback should return the correct default values):
+
+  AssertEqual
+  \ {
+  \   'command': ale#Escape('xxxinvalid') . ' tool format -',
+  \ },
+  \ ale#fixers#crystal#Fix(bufnr(''))
+
+Execute(The crystal format callback should include custom options):
+  let g:ale_crystal_format_options = "-list=true"
+
+  AssertEqual
+  \ {
+  \   'command': ale#Escape('xxxinvalid')
+  \     . ' tool format ' . g:ale_crystal_format_options
+  \     . ' -',
+  \ },
+  \ ale#fixers#crystal#Fix(bufnr(''))