Update the test suite so it uses the latest Docker image, and use Bourne shell for most tests, so weird shell issues are easier to catch.

Makefile

@@ -1,6 +1,6 @@
 SHELL := /usr/bin/env bash
 IMAGE ?= w0rp/ale
-CURRENT_IMAGE_ID = 82334204724d
+CURRENT_IMAGE_ID = 26d48d06e5e8
 DOCKER_FLAGS = --rm -v $(PWD):/testplugin -v $(PWD)/test:/home "$(IMAGE)"
 tests = test/*.vader test/*/*.vader test/*/*/*.vader test/*/*/*/*.vader
 

test/test_history_saving.vader

@@ -1,4 +1,8 @@
 Before:
+  " Temporarily set the shell to /bin/sh, if it isn't already set that way.
+  " This will make it so the test works when running it directly.
+  let g:current_shell = &shell
+  let &shell = '/bin/sh'
   let g:history = []
   let g:ale_buffer_info = {}
   let g:ale_max_buffer_history_size = 20
@@ -16,6 +20,9 @@ Before:
   \})
 
 After:
+  " Reset the shell back to what it was before.
+  let &shell = g:current_shell
+  unlet g:current_shell
   let g:ale_history_enabled = 1
   let g:ale_history_log_output = 0
   unlet g:history
@@ -37,7 +44,7 @@ Execute(History should be set when commands are run):
 
   AssertEqual 1, len(g:history)
   AssertEqual sort(['status', 'exit_code', 'job_id', 'command']), sort(keys(g:history[0]))
-  AssertEqual ['/bin/bash', '-c', 'echo command history test'], g:history[0].command
+  AssertEqual ['/bin/sh', '-c', 'echo command history test'], g:history[0].command
   AssertEqual 'finished', g:history[0].status
   AssertEqual 0, g:history[0].exit_code
   " The Job ID will change each time, but we can check the type.

test/vimrc

@@ -7,6 +7,7 @@ set runtimepath=/home/vim,$VIM/vimfiles,$VIMRUNTIME,$VIM/vimfiles/after,/testplu
 " The following is just an example
 filetype plugin indent on
 syntax on
+set shell=/bin/sh
 set nocompatible
 set tabstop=4
 set softtabstop=4