#1162 Add unfinished experimental code for supporting LSP completion, clean up the tests, and make the completion cancelling better

9 files changed, 677 insertions, 384 deletions

diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index e5f1dbbe..f8143903 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -2,8 +2,45 @@
 " Description: Completion support for LSP linters
 
 let s:timer_id = -1
+let s:last_done_pos = []
+
+" CompletionItemKind values from the LSP protocol.
+let s:LSP_COMPLETION_TEXT_KIND = 1
+let s:LSP_COMPLETION_METHOD_KIND = 2
+let s:LSP_COMPLETION_FUNCTION_KIND = 3
+let s:LSP_COMPLETION_CONSTRUCTOR_KIND = 4
+let s:LSP_COMPLETION_FIELD_KIND = 5
+let s:LSP_COMPLETION_VARIABLE_KIND = 6
+let s:LSP_COMPLETION_CLASS_KIND = 7
+let s:LSP_COMPLETION_INTERFACE_KIND = 8
+let s:LSP_COMPLETION_MODULE_KIND = 9
+let s:LSP_COMPLETION_PROPERTY_KIND = 10
+let s:LSP_COMPLETION_UNIT_KIND = 11
+let s:LSP_COMPLETION_VALUE_KIND = 12
+let s:LSP_COMPLETION_ENUM_KIND = 13
+let s:LSP_COMPLETION_KEYWORD_KIND = 14
+let s:LSP_COMPLETION_SNIPPET_KIND = 15
+let s:LSP_COMPLETION_COLOR_KIND = 16
+let s:LSP_COMPLETION_FILE_KIND = 17
+let s:LSP_COMPLETION_REFERENCE_KIND = 18
 
-function! s:GetRegex(map, filetype) abort
+" Regular expressions for checking the characters in the line before where
+" the insert cursor is. If one of these matches, we'll check for completions.
+let s:should_complete_map = {
+\   '<default>': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$',
+\}
+
+" Regular expressions for finding the start column to replace with completion.
+let s:omni_start_map = {
+\   '<default>': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$',
+\}
+
+" A map of exact characters for triggering LSP completions.
+let s:trigger_character_map = {
+\   '<default>': ['.'],
+\}
+
+function! s:GetFiletypeValue(map, filetype) abort
     for l:part in reverse(split(a:filetype, '\.'))
         let l:regex = get(a:map, l:part, [])
 
@@ -13,18 +50,12 @@ function! s:GetRegex(map, filetype) abort
     endfor
 
     " Use the default regex for other files.
-    return s:should_complete_map['<default>']
+    return a:map['<default>']
 endfunction
 
-" Regular expressions for checking the characters in the line before where
-" the insert cursor is. If one of these matches, we'll check for completions.
-let s:should_complete_map = {
-\   '<default>': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$',
-\}
-
 " Check if we should look for completions for a language.
 function! ale#completion#GetPrefix(filetype, line, column) abort
-    let l:regex = s:GetRegex(s:should_complete_map, a:filetype)
+    let l:regex = s:GetFiletypeValue(s:should_complete_map, a:filetype)
     " The column we're using completions for is where we are inserting text,
     " like so:
     "   abc
@@ -33,11 +64,15 @@ function! ale#completion#GetPrefix(filetype, line, column) abort
     return matchstr(getline(a:line)[: a:column - 2], l:regex)
 endfunction
 
-" Regular expressions for finding the start column to replace with completion.
-let s:omni_start_map = {
-\   'javascript': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$',
-\   'typescript': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$',
-\}
+function! ale#completion#GetTriggerCharacter(filetype, prefix) abort
+    let l:char_list = s:GetFiletypeValue(s:trigger_character_map, a:filetype)
+
+    if index(l:char_list, a:prefix) >= 0
+        return a:prefix
+    endif
+
+    return ''
+endfunction
 
 function! ale#completion#Filter(suggestions, prefix) abort
     " For completing...
@@ -82,7 +117,7 @@ function! ale#completion#OmniFunc(findstart, base) abort
     if a:findstart
         let l:line = b:ale_completion_info.line
         let l:column = b:ale_completion_info.column
-        let l:regex = s:GetRegex(s:omni_start_map, &filetype)
+        let l:regex = s:GetFiletypeValue(s:omni_start_map, &filetype)
         let l:up_to_column = getline(l:line)[: l:column - 2]
         let l:match = matchstr(l:up_to_column, l:regex)
 
@@ -180,7 +215,47 @@ function! ale#completion#ParseTSServerCompletionEntryDetails(response) abort
     return l:results
 endfunction
 
-function! ale#completion#HandleTSServerLSPResponse(conn_id, response) abort
+function! ale#completion#ParseLSPCompletions(response) abort
+    let l:item_list = []
+
+    if type(get(a:response, 'result')) is type([])
+        let l:item_list = a:response.result
+    elseif type(get(a:response, 'result')) is type({})
+    \&& type(get(a:response.result, 'items')) is type([])
+        let l:item_list = a:response.result.items
+    endif
+
+    let l:results = []
+
+    for l:item in l:item_list
+        " See :help complete-items for Vim completion kinds
+        if l:item.kind is s:LSP_COMPLETION_METHOD_KIND
+            let l:kind = 'm'
+        elseif l:item.kind is s:LSP_COMPLETION_CONSTRUCTOR_KIND
+            let l:kind = 'm'
+        elseif l:item.kind is s:LSP_COMPLETION_FUNCTION_KIND
+            let l:kind = 'f'
+        elseif l:item.kind is s:LSP_COMPLETION_CLASS_KIND
+            let l:kind = 'f'
+        elseif l:item.kind is s:LSP_COMPLETION_INTERFACE_KIND
+            let l:kind = 'f'
+        else
+            let l:kind = 'v'
+        endif
+
+        call add(l:results, {
+        \   'word': l:item.label,
+        \   'kind': l:kind,
+        \   'icase': 1,
+        \   'menu': l:item.detail,
+        \   'info': l:item.documentation,
+        \})
+    endfor
+
+    return l:results
+endfunction
+
+function! ale#completion#HandleTSServerResponse(conn_id, response) abort
     if !s:CompletionStillValid(get(a:response, 'request_seq'))
         return
     endif
@@ -216,28 +291,55 @@ function! ale#completion#HandleTSServerLSPResponse(conn_id, response) abort
     endif
 endfunction
 
+
+function! ale#completion#HandleLSPResponse(conn_id, response) abort
+    if !s:CompletionStillValid(get(a:response, 'id'))
+        return
+    endif
+
+    call ale#completion#Show(
+    \   a:response,
+    \   'ale#completion#ParseLSPCompletions',
+    \)
+endfunction
+
 function! s:GetLSPCompletions(linter) abort
     let l:buffer = bufnr('')
-    let l:lsp_details = ale#linter#StartLSP(
-    \   l:buffer,
-    \   a:linter,
-    \   function('ale#completion#HandleTSServerLSPResponse'),
-    \)
+    let l:Callback = a:linter.lsp is# 'tsserver'
+    \   ? function('ale#completion#HandleTSServerResponse')
+    \   : function('ale#completion#HandleLSPResponse')
+
+    let l:lsp_details = ale#linter#StartLSP(l:buffer, a:linter, l:Callback)
 
     if empty(l:lsp_details)
         return 0
     endif
 
     let l:id = l:lsp_details.connection_id
-    let l:command = l:lsp_details.command
     let l:root = l:lsp_details.project_root
 
-    let l:message = ale#lsp#tsserver_message#Completions(
-    \   l:buffer,
-    \   b:ale_completion_info.line,
-    \   b:ale_completion_info.column,
-    \   b:ale_completion_info.prefix,
-    \)
+    if a:linter.lsp is# 'tsserver'
+        let l:message = ale#lsp#tsserver_message#Completions(
+        \   l:buffer,
+        \   b:ale_completion_info.line,
+        \   b:ale_completion_info.column,
+        \   b:ale_completion_info.prefix,
+        \)
+    else
+        " For LSP completions, we need to clamp the column to the length of
+        " the line. python-language-server and perhaps others do not implement
+        " this correctly.
+        let l:message = ale#lsp#message#Completion(
+        \   l:buffer,
+        \   b:ale_completion_info.line,
+        \   min([
+        \       b:ale_completion_info.line_length,
+        \       b:ale_completion_info.column
+        \   ]),
+        \   '',
+        \)
+    endif
+
     let l:request_id = ale#lsp#Send(l:id, l:message, l:root)
 
     if l:request_id
@@ -247,6 +349,10 @@ function! s:GetLSPCompletions(linter) abort
 endfunction
 
 function! ale#completion#GetCompletions() abort
+    if !g:ale_completion_enabled
+        return
+    endif
+
     let [l:line, l:column] = getcurpos()[1:2]
 
     let l:prefix = ale#completion#GetPrefix(&filetype, l:line, l:column)
@@ -255,8 +361,11 @@ function! ale#completion#GetCompletions() abort
         return
     endif
 
+    let l:line_length = len(getline('.'))
+
     let b:ale_completion_info = {
     \   'line': l:line,
+    \   'line_length': l:line_length,
     \   'column': l:column,
     \   'prefix': l:prefix,
     \   'conn_id': 0,
@@ -264,8 +373,11 @@ function! ale#completion#GetCompletions() abort
     \}
 
     for l:linter in ale#linter#Get(&filetype)
-        if l:linter.lsp is# 'tsserver'
-            call s:GetLSPCompletions(l:linter)
+        if !empty(l:linter.lsp)
+            if l:linter.lsp is# 'tsserver'
+            \|| get(g:, 'ale_completion_experimental_lsp_support', 0)
+                call s:GetLSPCompletions(l:linter)
+            endif
         endif
     endfor
 endfunction
@@ -292,15 +404,18 @@ function! ale#completion#StopTimer() abort
 endfunction
 
 function! ale#completion#Queue() abort
-    let l:time = get(b:, 'ale_complete_done_time', 0)
-
-    if l:time && ale#util#ClockMilliseconds() - l:time < 100
-        " Do not ask for completions shortly after we just closed the menu.
+    if !g:ale_completion_enabled
         return
     endif
 
     let s:timer_pos = getcurpos()[1:2]
 
+    if s:timer_pos == s:last_done_pos
+        " Do not ask for completions if the cursor rests on the position we
+        " last completed on.
+        return
+    endif
+
     " If we changed the text again while we're still waiting for a response,
     " then invalidate the requests before the timer ticks again.
     if exists('b:ale_completion_info')
@@ -317,7 +432,10 @@ function! ale#completion#Done() abort
 
     " Reset settings when completion is done.
     if exists('b:ale_old_omnifunc')
-        let &l:omnifunc = b:ale_old_omnifunc
+        if b:ale_old_omnifunc isnot# 'pythoncomplete#Complete'
+            let &l:omnifunc = b:ale_old_omnifunc
+        endif
+
         unlet b:ale_old_omnifunc
     endif
 
@@ -326,8 +444,7 @@ function! ale#completion#Done() abort
         unlet b:ale_old_completopt
     endif
 
-    " Set a timestamp, so we can avoid requesting completions again.
-    let b:ale_complete_done_time = ale#util#ClockMilliseconds()
+    let s:last_done_pos = getcurpos()[1:2]
 endfunction
 
 function! s:Setup(enabled) abort
diff --git a/autoload/ale/lsp/message.vim b/autoload/ale/lsp/message.vim
index 31a9b210..a90d4e75 100644
--- a/autoload/ale/lsp/message.vim
+++ b/autoload/ale/lsp/message.vim
@@ -86,3 +86,24 @@ function! ale#lsp#message#DidClose(buffer) abort
     \   },
     \}]
 endfunction
+
+let s:COMPLETION_TRIGGER_INVOKED = 1
+let s:COMPLETION_TRIGGER_CHARACTER = 2
+
+function! ale#lsp#message#Completion(buffer, line, column, trigger_character) abort
+    let l:message = [0, 'textDocument/completion', {
+    \   'textDocument': {
+    \       'uri': ale#path#ToURI(expand('#' . a:buffer . ':p')),
+    \   },
+    \   'position': {'line': a:line - 1, 'character': a:column - 1},
+    \}]
+
+    if !empty(a:trigger_character)
+        let l:message[2].context = {
+        \   'triggerKind': s:COMPLETION_TRIGGER_CHARACTER,
+        \   'triggerCharacter': a:trigger_character,
+        \}
+    endif
+
+    return l:message
+endfunction
diff --git a/test/completion/test_completion_events.vader b/test/completion/test_completion_events.vader
new file mode 100644
index 00000000..49d485f6
--- /dev/null
+++ b/test/completion/test_completion_events.vader
@@ -0,0 +1,172 @@
+Before:
+  Save g:ale_completion_enabled
+  Save g:ale_completion_delay
+  Save g:ale_completion_max_suggestions
+  Save g:ale_completion_experimental_lsp_support
+  Save &l:omnifunc
+  Save &l:completeopt
+
+  unlet! g:ale_completion_experimental_lsp_support
+
+  let g:ale_completion_enabled = 1
+  let g:get_completions_called = 0
+  let g:feedkeys_calls = []
+
+  runtime autoload/ale/util.vim
+
+  function! ale#util#FeedKeys(string, mode) abort
+    call add(g:feedkeys_calls, [a:string, a:mode])
+  endfunction
+
+  function! CheckCompletionCalled(expect_success) abort
+    let g:get_completions_called = 0
+
+    " We just want to check if the function is called.
+    function! ale#completion#GetCompletions()
+      let g:get_completions_called = 1
+    endfunction
+
+    let g:ale_completion_delay = 0
+    call ale#completion#Queue()
+    sleep 1m
+
+    AssertEqual a:expect_success, g:get_completions_called
+  endfunction
+
+After:
+  Restore
+
+  unlet! g:get_completions_called
+  unlet! b:ale_old_omnifunc
+  unlet! b:ale_old_completopt
+  unlet! b:ale_completion_info
+  unlet! b:ale_completion_response
+  unlet! b:ale_completion_parser
+  unlet! b:ale_complete_done_time
+  unlet! g:ale_completion_experimental_lsp_support
+
+  delfunction CheckCompletionCalled
+
+  " Stop any timers we left behind.
+  " This stops the tests from failing randomly.
+  call ale#completion#StopTimer()
+
+  runtime autoload/ale/completion.vim
+  runtime autoload/ale/util.vim
+
+Execute(ale#completion#GetCompletions should be called when the cursor position stays the same):
+  call CheckCompletionCalled(1)
+
+Given typescript():
+  let abc = y.
+  let foo = ab
+  let foo = (ab)
+
+Execute(ale#completion#GetCompletions should not be called when the cursor position changes):
+  call setpos('.', [bufnr(''), 1, 2, 0])
+
+  " We just want to check if the function is called.
+  function! ale#completion#GetCompletions()
+    let g:get_completions_called = 1
+  endfunction
+
+  let g:ale_completion_delay = 0
+  call ale#completion#Queue()
+
+  " Change the cursor position before the callback is triggered.
+  call setpos('.', [bufnr(''), 2, 2, 0])
+
+  sleep 1m
+
+  Assert !g:get_completions_called
+
+Execute(Completion should not be done shortly after the CompleteDone function):
+  call CheckCompletionCalled(1)
+  call ale#completion#Done()
+  call CheckCompletionCalled(0)
+
+Execute(ale#completion#Show() should remember the omnifunc setting and replace it):
+  let &l:omnifunc = 'FooBar'
+
+  call ale#completion#Show('Response', 'Parser')
+
+  AssertEqual 'FooBar', b:ale_old_omnifunc
+  AssertEqual 'ale#completion#OmniFunc', &l:omnifunc
+
+Execute(ale#completion#Show() should remember the completeopt setting and replace it):
+  let &l:completeopt = 'menu'
+
+  call ale#completion#Show('Response', 'Parser')
+
+  AssertEqual 'menu', b:ale_old_completopt
+  AssertEqual 'menu,menuone,preview,noselect,noinsert', &l:completeopt
+
+Execute(ale#completion#OmniFunc() should also remember the completeopt setting and replace it):
+  let &l:completeopt = 'menu'
+
+  call ale#completion#OmniFunc(0, '')
+
+  AssertEqual 'menu', b:ale_old_completopt
+  AssertEqual 'menu,menuone,preview,noselect,noinsert', &l:completeopt
+
+Execute(ale#completion#Show() should make the correct feedkeys() call):
+  call ale#completion#Show('Response', 'Parser')
+
+  AssertEqual [["\<C-x>\<C-o>", 'n']], g:feedkeys_calls
+
+Execute(ale#completion#Show() should set up the response and parser):
+  call ale#completion#Show('Response', 'Parser')
+
+  AssertEqual 'Response', b:ale_completion_response
+  AssertEqual 'Parser', b:ale_completion_parser
+
+Execute(ale#completion#Done() should restore old omnifunc values):
+  let b:ale_old_omnifunc = 'FooBar'
+
+  call ale#completion#Done()
+
+  " We reset the old omnifunc setting and remove the buffer variable.
+  AssertEqual 'FooBar', &l:omnifunc
+  Assert !has_key(b:, 'ale_old_omnifunc')
+
+Execute(ale#completion#Done() should restore the old completeopt setting):
+  let b:ale_old_completopt = 'menu'
+  let &l:completeopt = 'menu,menuone,preview,noselect,noinsert'
+
+  call ale#completion#Done()
+
+  AssertEqual 'menu', &l:completeopt
+  Assert !has_key(b:, 'ale_old_completopt')
+
+Execute(ale#completion#Done() should leave settings alone when none were remembered):
+  let &l:omnifunc = 'BazBoz'
+  let &l:completeopt = 'menu'
+
+  call ale#completion#Done()
+
+  AssertEqual 'BazBoz', &l:omnifunc
+  AssertEqual 'menu', &l:completeopt
+
+Execute(The completion request_id should be reset when queuing again):
+  let b:ale_completion_info = {'request_id': 123}
+
+  let g:ale_completion_delay = 0
+  call ale#completion#Queue()
+  sleep 1m
+
+  AssertEqual 0, b:ale_completion_info.request_id
+
+Execute(b:ale_completion_info should be set up correctly when requesting completions):
+  call setpos('.', [bufnr(''), 3, 14, 0])
+  call ale#completion#GetCompletions()
+
+  AssertEqual
+  \ {
+  \   'request_id': 0,
+  \   'conn_id': 0,
+  \   'column': 14,
+  \   'line_length': 14,
+  \   'line': 3,
+  \   'prefix': 'ab',
+  \ },
+  \ b:ale_completion_info
diff --git a/test/completion/test_completion_filtering.vader b/test/completion/test_completion_filtering.vader
new file mode 100644
index 00000000..3e461aef
--- /dev/null
+++ b/test/completion/test_completion_filtering.vader
@@ -0,0 +1,36 @@
+Execute(Prefix filtering should work for Lists of strings):
+  AssertEqual
+  \ ['FooBar', 'foo'],
+  \ ale#completion#Filter(['FooBar', 'FongBar', 'baz', 'foo'], 'foo')
+  AssertEqual
+  \ ['FooBar', 'FongBar', 'baz', 'foo'],
+  \ ale#completion#Filter(['FooBar', 'FongBar', 'baz', 'foo'], '.')
+
+Execute(Prefix filtering should work for completion items):
+  AssertEqual
+  \ [{'word': 'FooBar'}, {'word': 'foo'}],
+  \ ale#completion#Filter(
+  \   [
+  \     {'word': 'FooBar'},
+  \     {'word': 'FongBar'},
+  \     {'word': 'baz'},
+  \     {'word': 'foo'},
+  \   ],
+  \   'foo'
+  \ )
+  AssertEqual
+  \ [
+  \   {'word': 'FooBar'},
+  \   {'word': 'FongBar'},
+  \   {'word': 'baz'},
+  \   {'word': 'foo'},
+  \ ],
+  \ ale#completion#Filter(
+  \   [
+  \     {'word': 'FooBar'},
+  \     {'word': 'FongBar'},
+  \     {'word': 'baz'},
+  \     {'word': 'foo'},
+  \   ],
+  \   '.'
+  \ )
diff --git a/test/completion/test_completion_prefixes.vader b/test/completion/test_completion_prefixes.vader
new file mode 100644
index 00000000..8ac29326
--- /dev/null
+++ b/test/completion/test_completion_prefixes.vader
@@ -0,0 +1,19 @@
+Given typescript():
+  let abc = y.
+  let foo = ab
+  let foo = (ab)
+
+Execute(Completion should be done after dots in TypeScript):
+  AssertEqual '.', ale#completion#GetPrefix(&filetype, 1, 13)
+
+Execute(Completion should be done after words in TypeScript):
+  AssertEqual 'ab', ale#completion#GetPrefix(&filetype, 2, 13)
+
+Execute(Completion should be done after words in parens in TypeScript):
+  AssertEqual 'ab', ale#completion#GetPrefix(&filetype, 3, 14)
+
+Execute(Completion should not be done after parens in TypeScript):
+  AssertEqual '', ale#completion#GetPrefix(&filetype, 3, 15)
+
+Execute(Completion prefixes should work for other filetypes):
+  AssertEqual 'ab', ale#completion#GetPrefix('xxxyyyzzz', 3, 14)
diff --git a/test/completion/test_lsp_completion_messages.vader b/test/completion/test_lsp_completion_messages.vader
new file mode 100644
index 00000000..df340fbe
--- /dev/null
+++ b/test/completion/test_lsp_completion_messages.vader
@@ -0,0 +1,171 @@
+Before:
+  Save g:ale_completion_delay
+  Save g:ale_completion_max_suggestions
+  Save g:ale_completion_info
+  Save g:ale_completion_experimental_lsp_support
+  Save &l:omnifunc
+  Save &l:completeopt
+
+  unlet! g:ale_completion_experimental_lsp_support
+
+  let g:ale_completion_enabled = 1
+
+  call ale#test#SetDirectory('/testplugin/test/completion')
+  call ale#test#SetFilename('dummy.txt')
+
+  runtime autoload/ale/lsp.vim
+
+  let g:message = []
+  let g:Callback = ''
+
+  function! ale#linter#StartLSP(buffer, linter, callback) abort
+    let g:Callback = a:callback
+
+    return {
+    \ 'connection_id': 347,
+    \ 'project_root': '/foo/bar',
+    \}
+  endfunction
+
+  " Replace the Send function for LSP, so we can monitor calls to it.
+  function! ale#lsp#Send(conn_id, message, ...) abort
+    let g:message = a:message
+  endfunction
+
+After:
+  Restore
+
+  unlet! g:message
+  unlet! g:Callback
+  unlet! b:ale_old_omnifunc
+  unlet! b:ale_old_completopt
+  unlet! b:ale_completion_info
+  unlet! b:ale_completion_response
+  unlet! b:ale_completion_parser
+  unlet! b:ale_complete_done_time
+  unlet! b:ale_linters
+  unlet! g:ale_completion_experimental_lsp_support
+
+  call ale#test#RestoreDirectory()
+  call ale#linter#Reset()
+
+  " Stop any timers we left behind.
+  " This stops the tests from failing randomly.
+  call ale#completion#StopTimer()
+
+  runtime autoload/ale/completion.vim
+  runtime autoload/ale/lsp.vim
+
+Given typescript(Some typescript file):
+  foo
+  somelongerline
+  bazxyzxyzxyz
+
+Execute(The right message should be sent for the initial tsserver request):
+  runtime ale_linters/typescript/tsserver.vim
+  let b:ale_linters = ['tsserver']
+  " The cursor position needs to match what was saved before.
+  call setpos('.', [bufnr(''), 1, 3, 0])
+
+  call ale#completion#GetCompletions()
+
+  " We should send the right callback.
+  AssertEqual
+  \ 'function(''ale#completion#HandleTSServerResponse'')',
+  \ string(g:Callback)
+  " We should send the right message.
+  AssertEqual
+  \ [0, 'ts@completions', {'file': expand('%:p'), 'line': 1, 'offset': 3, 'prefix': 'fo'}],
+  \ g:message
+  " We should set up the completion info correctly.
+  AssertEqual
+  \ {
+  \   'line_length': 3,
+  \   'conn_id': 0,
+  \   'column': 3,
+  \   'request_id': 0,
+  \   'line': 1,
+  \   'prefix': 'fo',
+  \ },
+  \ get(b:, 'ale_completion_info', {})
+
+Execute(The right message sent to the tsserver LSP when the first completion message is received):
+  " The cursor position needs to match what was saved before.
+  call setpos('.', [bufnr(''), 1, 1, 0])
+  let b:ale_completion_info = {
+  \ 'conn_id': 123,
+  \ 'prefix': 'f',
+  \ 'request_id': 4,
+  \ 'line': 1,
+  \ 'column': 1,
+  \}
+  " We should only show up to this many suggestions.
+  let g:ale_completion_max_suggestions = 3
+
+  " Handle the response for completions.
+  call ale#completion#HandleTSServerResponse(123, {
+  \ 'request_seq': 4,
+  \ 'command': 'completions',
+  \ 'body': [
+  \   {'name': 'Baz'},
+  \   {'name': 'dingDong'},
+  \   {'name': 'Foo'},
+  \   {'name': 'FooBar'},
+  \   {'name': 'frazzle'},
+  \   {'name': 'FFS'},
+  \ ],
+  \})
+
+  " The entry details messages should have been sent.
+  AssertEqual
+  \ [
+  \   0,
+  \   'ts@completionEntryDetails',
+  \   {
+  \     'file': expand('%:p'),
+  \     'entryNames': ['Foo', 'FooBar', 'frazzle'],
+  \     'offset': 1,
+  \     'line': 1,
+  \   },
+  \ ],
+  \ g:message
+
+Given python(Some Python file):
+  foo
+  somelongerline
+  bazxyzxyzxyz
+
+Execute(The right message should be sent for the initial LSP request):
+  let g:ale_completion_experimental_lsp_support = 1
+
+  runtime ale_linters/python/pyls.vim
+  let b:ale_linters = ['pyls']
+  " The cursor position needs to match what was saved before.
+  call setpos('.', [bufnr(''), 1, 5, 0])
+
+  call ale#completion#GetCompletions()
+
+  " We should send the right callback.
+  AssertEqual
+  \ 'function(''ale#completion#HandleLSPResponse'')',
+  \ string(g:Callback)
+  " We should send the right message.
+  " The character index needs to be at most the index of the last character on
+  " the line, or integration with pyls will be broken.
+  AssertEqual
+  \ [0, 'textDocument/completion', {
+  \   'textDocument': {'uri': ale#path#ToURI(expand('%:p'))},
+  \   'position': {'line': 0, 'character': 2},
+  \ }],
+  \ g:message
+  " We should set up the completion info correctly.
+  AssertEqual
+  \ {
+  \   'line_length': 3,
+  \   'conn_id': 0,
+  \   'column': 3,
+  \   'request_id': 0,
+  \   'line': 1,
+  \   'prefix': 'fo',
+  \ },
+  \ get(b:, 'ale_completion_info', {})
diff --git a/test/completion/test_tsserver_completion_parsing.vader b/test/completion/test_tsserver_completion_parsing.vader
new file mode 100644
index 00000000..b663ef40
--- /dev/null
+++ b/test/completion/test_tsserver_completion_parsing.vader
@@ -0,0 +1,75 @@
+Execute(TypeScript completions responses should be parsed correctly):
+  AssertEqual [],
+  \ ale#completion#ParseTSServerCompletions({
+  \ 'body': [],
+  \})
+  AssertEqual ['foo', 'bar', 'baz'],
+  \ ale#completion#ParseTSServerCompletions({
+  \ 'body': [
+  \   {'name': 'foo'},
+  \   {'name': 'bar'},
+  \   {'name': 'baz'},
+  \ ],
+  \})
+
+Execute(TypeScript completion details responses should be parsed correctly):
+  AssertEqual
+  \ [
+  \   {
+  \     'word': 'abc',
+  \     'menu': '(property) Foo.abc: number',
+  \     'info': '',
+  \     'kind': 'f',
+  \     'icase': 1,
+  \   },
+  \   {
+  \     'word': 'def',
+  \     'menu': '(property) Foo.def: number',
+  \     'info': 'foo bar baz',
+  \     'kind': 'f',
+  \     'icase': 1,
+  \   },
+  \ ],
+  \ ale#completion#ParseTSServerCompletionEntryDetails({
+  \ 'body': [
+  \   {
+  \     'name': 'abc',
+  \     'kind': 'parameterName',
+  \     'displayParts': [
+  \       {'text': '('},
+  \       {'text': 'property'},
+  \       {'text': ')'},
+  \       {'text': ' '},
+  \       {'text': 'Foo'},
+  \       {'text': '.'},
+  \       {'text': 'abc'},
+  \       {'text': ':'},
+  \       {'text': ' '},
+  \       {'text': 'number'},
+  \     ],
+  \   },
+  \   {
+  \     'name': 'def',
+  \     'kind': 'parameterName',
+  \     'displayParts': [
+  \       {'text': '('},
+  \       {'text': 'property'},
+  \       {'text': ')'},
+  \       {'text': ' '},
+  \       {'text': 'Foo'},
+  \       {'text': '.'},
+  \       {'text': 'def'},
+  \       {'text': ':'},
+  \       {'text': ' '},
+  \       {'text': 'number'},
+  \     ],
+  \     'documentation': [
+  \       {'text': 'foo'},
+  \       {'text': ' '},
+  \       {'text': 'bar'},
+  \       {'text': ' '},
+  \       {'text': 'baz'},
+  \     ],
+  \   },
+  \ ],
+  \})
diff --git a/test/lsp/test_lsp_client_messages.vader b/test/lsp/test_lsp_client_messages.vader
index c6d82b60..bd0cd102 100644
--- a/test/lsp/test_lsp_client_messages.vader
+++ b/test/lsp/test_lsp_client_messages.vader
@@ -101,6 +101,35 @@ Execute(ale#lsp#message#DidClose() should return correct messages):
   \ ],
   \ ale#lsp#message#DidClose(bufnr(''))
 
+Execute(ale#lsp#message#Completion() should return correct messages):
+  AssertEqual
+  \ [
+  \   0,
+  \   'textDocument/completion',
+  \   {
+  \     'textDocument': {
+  \         'uri': ale#path#ToURI(g:dir . '/foo/bar.ts'),
+  \     },
+  \     'position': {'line': 11, 'character': 33},
+  \   }
+  \ ],
+  \ ale#lsp#message#Completion(bufnr(''), 12, 34, '')
+
+Execute(ale#lsp#message#Completion() should return correct messages with a trigger charaacter):
+  AssertEqual
+  \ [
+  \   0,
+  \   'textDocument/completion',
+  \   {
+  \     'textDocument': {
+  \         'uri': ale#path#ToURI(g:dir . '/foo/bar.ts'),
+  \     },
+  \     'position': {'line': 11, 'character': 33},
+  \     'context': {'triggerKind': 2, 'triggerCharacter': '.'},
+  \   }
+  \ ],
+  \ ale#lsp#message#Completion(bufnr(''), 12, 34, '.')
+
 Execute(ale#lsp#tsserver_message#Open() should return correct messages):
   AssertEqual
   \ [
diff --git a/test/test_completion.vader b/test/test_completion.vader
deleted file mode 100644
index 9662fc28..00000000
--- a/test/test_completion.vader
+++ /dev/null
@@ -1,347 +0,0 @@
-Before:
-  Save g:ale_completion_enabled
-  Save g:ale_completion_delay
-  Save g:ale_completion_max_suggestions
-  Save &l:omnifunc
-  Save &l:completeopt
-
-  let g:test_vars = {
-  \ 'feedkeys_calls': [],
-  \}
-
-  function! ale#util#FeedKeys(string, mode) abort
-    call add(g:test_vars.feedkeys_calls, [a:string, a:mode])
-  endfunction
-
-  function! CheckCompletionCalled(expect_success) abort
-    let g:test_vars.get_completions_called = 0
-
-    " We just want to check if the function is called.
-    function! ale#completion#GetCompletions()
-      let g:test_vars.get_completions_called = 1
-    endfunction
-
-    let g:ale_completion_delay = 0
-    call ale#completion#Queue()
-    sleep 1m
-
-    AssertEqual a:expect_success, g:test_vars.get_completions_called
-  endfunction
-
-After:
-  Restore
-
-  unlet! g:test_vars
-  unlet! b:ale_old_omnifunc
-  unlet! b:ale_old_completopt
-  unlet! b:ale_completion_info
-  unlet! b:ale_completion_response
-  unlet! b:ale_completion_parser
-  unlet! b:ale_complete_done_time
-
-  delfunction CheckCompletionCalled
-
-  " Stop any timers we left behind.
-  " This stops the tests from failing randomly.
-  call ale#completion#StopTimer()
-
-  runtime autoload/ale/completion.vim
-  runtime autoload/ale/lsp.vim
-
-  if g:ale_completion_enabled
-    call ale#completion#Enable()
-  else
-    call ale#completion#Disable()
-  endif
-
-Execute(TypeScript completions responses should be parsed correctly):
-  AssertEqual [],
-  \ ale#completion#ParseTSServerCompletions({
-  \ 'body': [],
-  \})
-  AssertEqual ['foo', 'bar', 'baz'],
-  \ ale#completion#ParseTSServerCompletions({
-  \ 'body': [
-  \   {'name': 'foo'},
-  \   {'name': 'bar'},
-  \   {'name': 'baz'},
-  \ ],
-  \})
-
-Execute(TypeScript completion details responses should be parsed correctly):
-  AssertEqual
-  \ [
-  \   {
-  \     'word': 'abc',
-  \     'menu': '(property) Foo.abc: number',
-  \     'info': '',
-  \     'kind': 'f',
-  \     'icase': 1,
-  \   },
-  \   {
-  \     'word': 'def',
-  \     'menu': '(property) Foo.def: number',
-  \     'info': 'foo bar baz',
-  \     'kind': 'f',
-  \     'icase': 1,
-  \   },
-  \ ],
-  \ ale#completion#ParseTSServerCompletionEntryDetails({
-  \ 'body': [
-  \   {
-  \     'name': 'abc',
-  \     'kind': 'parameterName',
-  \     'displayParts': [
-  \       {'text': '('},
-  \       {'text': 'property'},
-  \       {'text': ')'},
-  \       {'text': ' '},
-  \       {'text': 'Foo'},
-  \       {'text': '.'},
-  \       {'text': 'abc'},
-  \       {'text': ':'},
-  \       {'text': ' '},
-  \       {'text': 'number'},
-  \     ],
-  \   },
-  \   {
-  \     'name': 'def',
-  \     'kind': 'parameterName',
-  \     'displayParts': [
-  \       {'text': '('},
-  \       {'text': 'property'},
-  \       {'text': ')'},
-  \       {'text': ' '},
-  \       {'text': 'Foo'},
-  \       {'text': '.'},
-  \       {'text': 'def'},
-  \       {'text': ':'},
-  \       {'text': ' '},
-  \       {'text': 'number'},
-  \     ],
-  \     'documentation': [
-  \       {'text': 'foo'},
-  \       {'text': ' '},
-  \       {'text': 'bar'},
-  \       {'text': ' '},
-  \       {'text': 'baz'},
-  \     ],
-  \   },
-  \ ],
-  \})
-
-Execute(Prefix filtering should work for Lists of strings):
-  AssertEqual
-  \ ['FooBar', 'foo'],
-  \ ale#completion#Filter(['FooBar', 'FongBar', 'baz', 'foo'], 'foo')
-  AssertEqual
-  \ ['FooBar', 'FongBar', 'baz', 'foo'],
-  \ ale#completion#Filter(['FooBar', 'FongBar', 'baz', 'foo'], '.')
-
-Execute(Prefix filtering should work for completion items):
-  AssertEqual
-  \ [{'word': 'FooBar'}, {'word': 'foo'}],
-  \ ale#completion#Filter(
-  \   [
-  \     {'word': 'FooBar'},
-  \     {'word': 'FongBar'},
-  \     {'word': 'baz'},
-  \     {'word': 'foo'},
-  \   ],
-  \   'foo'
-  \ )
-  AssertEqual
-  \ [
-  \   {'word': 'FooBar'},
-  \   {'word': 'FongBar'},
-  \   {'word': 'baz'},
-  \   {'word': 'foo'},
-  \ ],
-  \ ale#completion#Filter(
-  \   [
-  \     {'word': 'FooBar'},
-  \     {'word': 'FongBar'},
-  \     {'word': 'baz'},
-  \     {'word': 'foo'},
-  \   ],
-  \   '.'
-  \ )
-
-Execute(The right message sent to the tsserver LSP when the first completion message is received):
-  " The cursor position needs to match what was saved before.
-  call setpos('.', [bufnr(''), 1, 1, 0])
-  let b:ale_completion_info = {
-  \ 'conn_id': 123,
-  \ 'prefix': 'f',
-  \ 'request_id': 4,
-  \ 'line': 1,
-  \ 'column': 1,
-  \}
-  " We should only show up to this many suggestions.
-  let g:ale_completion_max_suggestions = 3
-
-  " Replace the Send function for LSP, so we can monitor calls to it.
-  function! ale#lsp#Send(conn_id, message) abort
-    let g:test_vars.message = a:message
-  endfunction
-
-  " Handle the response for completions.
-  call ale#completion#HandleTSServerLSPResponse(123, {
-  \ 'request_seq': 4,
-  \ 'command': 'completions',
-  \ 'body': [
-  \   {'name': 'Baz'},
-  \   {'name': 'dingDong'},
-  \   {'name': 'Foo'},
-  \   {'name': 'FooBar'},
-  \   {'name': 'frazzle'},
-  \   {'name': 'FFS'},
-  \ ],
-  \})
-
-  " The entry details messages should have been sent.
-  AssertEqual
-  \ [
-  \   0,
-  \   'ts@completionEntryDetails',
-  \   {
-  \     'file': expand('%:p'),
-  \     'entryNames': ['Foo', 'FooBar', 'frazzle'],
-  \     'offset': 1,
-  \     'line': 1,
-  \   },
-  \ ],
-  \ g:test_vars.message
-
-Given typescript():
-  let abc = y.
-  let foo = ab
-  let foo = (ab)
-
-Execute(Completion should be done after dots in TypeScript):
-  AssertEqual '.', ale#completion#GetPrefix(&filetype, 1, 13)
-
-Execute(Completion should be done after words in TypeScript):
-  AssertEqual 'ab', ale#completion#GetPrefix(&filetype, 2, 13)
-
-Execute(Completion should be done after words in parens in TypeScript):
-  AssertEqual 'ab', ale#completion#GetPrefix(&filetype, 3, 14)
-
-Execute(Completion should not be done after parens in TypeScript):
-  AssertEqual '', ale#completion#GetPrefix(&filetype, 3, 15)
-
-Execute(Completion prefixes should work for other filetypes):
-  AssertEqual 'ab', ale#completion#GetPrefix('xxxyyyzzz', 3, 14)
-
-Execute(ale#completion#Show() should remember the omnifunc setting and replace it):
-  let &l:omnifunc = 'FooBar'
-
-  call ale#completion#Show('Response', 'Parser')
-
-  AssertEqual 'FooBar', b:ale_old_omnifunc
-  AssertEqual 'ale#completion#OmniFunc', &l:omnifunc
-
-Execute(ale#completion#Show() should remember the completeopt setting and replace it):
-  let &l:completeopt = 'menu'
-
-  call ale#completion#Show('Response', 'Parser')
-
-  AssertEqual 'menu', b:ale_old_completopt
-  AssertEqual 'menu,menuone,preview,noselect,noinsert', &l:completeopt
-
-Execute(ale#completion#OmniFunc() should also remember the completeopt setting and replace it):
-  let &l:completeopt = 'menu'
-
-  call ale#completion#OmniFunc(0, '')
-
-  AssertEqual 'menu', b:ale_old_completopt
-  AssertEqual 'menu,menuone,preview,noselect,noinsert', &l:completeopt
-
-Execute(ale#completion#Show() should make the correct feedkeys() call):
-  call ale#completion#Show('Response', 'Parser')
-
-  AssertEqual [["\<C-x>\<C-o>", 'n']], g:test_vars.feedkeys_calls
-
-Execute(ale#completion#Show() should set up the response and parser):
-  call ale#completion#Show('Response', 'Parser')
-
-  AssertEqual 'Response', b:ale_completion_response
-  AssertEqual 'Parser', b:ale_completion_parser
-
-Execute(ale#completion#Done() should restore old omnifunc values):
-  let b:ale_old_omnifunc = 'FooBar'
-
-  call ale#completion#Done()
-
-  " We reset the old omnifunc setting and remove the buffer variable.
-  AssertEqual 'FooBar', &l:omnifunc
-  Assert !has_key(b:, 'ale_old_omnifunc')
-
-Execute(ale#completion#Done() should restore the old completeopt setting):
-  let b:ale_old_completopt = 'menu'
-  let &l:completeopt = 'menu,menuone,preview,noselect,noinsert'
-
-  call ale#completion#Done()
-
-  AssertEqual 'menu', &l:completeopt
-  Assert !has_key(b:, 'ale_old_completopt')
-
-Execute(ale#completion#Done() should leave settings alone when none were remembered):
-  let &l:omnifunc = 'BazBoz'
-  let &l:completeopt = 'menu'
-
-  call ale#completion#Done()
-
-  AssertEqual 'BazBoz', &l:omnifunc
-  AssertEqual 'menu', &l:completeopt
-
-Execute(The completion request_id should be reset when queuing again):
-  let b:ale_completion_info = {'request_id': 123}
-
-  let g:ale_completion_delay = 0
-  call ale#completion#Queue()
-  sleep 1m
-
-  AssertEqual 0, b:ale_completion_info.request_id
-
-Execute(b:ale_completion_info should be set up correctly when requesting completions):
-  call setpos('.', [bufnr(''), 3, 14, 0])
-  call ale#completion#GetCompletions()
-
-  AssertEqual
-  \ {
-  \   'request_id': 0,
-  \   'conn_id': 0,
-  \   'column': 14,
-  \   'line': 3,
-  \   'prefix': 'ab',
-  \ },
-  \ b:ale_completion_info
-
-Execute(ale#completion#GetCompletions should be called when the cursor position stays the same):
-  call CheckCompletionCalled(1)
-
-Execute(ale#completion#GetCompletions should not be called when the cursor position changes):
-  call setpos('.', [bufnr(''), 1, 2, 0])
-
-  let g:test_vars.get_completions_called = 0
-
-  " We just want to check if the function is called.
-  function! ale#completion#GetCompletions()
-    let g:test_vars.get_completions_called = 1
-  endfunction
-
-  let g:ale_completion_delay = 0
-  call ale#completion#Queue()
-
-  " Change the cursor position before the callback is triggered.
-  call setpos('.', [bufnr(''), 2, 2, 0])
-
-  sleep 1m
-
-  Assert !g:test_vars.get_completions_called
-
-Execute(Completion should not be done shortly after the CompleteDone function):
-  call CheckCompletionCalled(1)
-  call ale#completion#Done()
-  call CheckCompletionCalled(0)