Before:
  let g:linter = {}

After:
  unlet g:linter

Execute (PreProcess should throw when the linter object is not a Dictionary):
  AssertThrows call ale#linter#PreProcess('')
  AssertEqual 'The linter object must be a Dictionary', g:vader_exception

Execute (PreProcess should throw when there is no name):
  AssertThrows call ale#linter#PreProcess({
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \})
  AssertEqual '`name` must be defined to name the linter', g:vader_exception

Execute (PreProcess should throw when there is no callback):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \})
  AssertEqual '`callback` must be defined with a callback to accept output', g:vader_exception

Execute (PreProcess should throw when then callback is not a function):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 1,
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \})
  AssertEqual '`callback` must be defined with a callback to accept output', g:vader_exception

Execute (PreProcess should throw when there is no executable or executable_callback):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'command': 'echo',
  \})
  AssertEqual 'Either `executable` or `executable_callback` must be defined', g:vader_exception

Execute (PreProcess should throw when executable is not a string):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 123,
  \ 'command': 'echo',
  \})
  AssertEqual '`executable` must be a string if defined', g:vader_exception

Execute (PreProcess should throw when executable_callback is not a callback):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable_callback': 123,
  \ 'command': 'echo',
  \})
  AssertEqual '`executable_callback` must be a callback if defined', g:vader_exception

Execute (PreProcess should throw when there is no command):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \})
  AssertEqual 'Either `command`, `executable_callback`, `command_chain` must be defined', g:vader_exception

Execute (PreProcess should throw when command is not a string):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': [],
  \})
  AssertEqual '`command` must be a string if defined', g:vader_exception

Execute (PreProcess should throw when command_callback is not a callback):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command_callback': 123,
  \})
  AssertEqual '`command_callback` must be a callback if defined', g:vader_exception

Execute (PreProcess should when the output stream isn't a valid string):
  AssertThrows call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \ 'output_stream': 'xxx',
  \})
  AssertEqual "`output_stream` must be 'stdout', 'stderr', or 'both'", g:vader_exception

Execute (PreProcess should not throw when everything is correct):
  call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \})

Execute (PreProcess should accept an stdout output_stream):
  call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \ 'output_stream': 'stdout',
  \})

Execute (PreProcess should accept an stderr output_stream):
  call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \ 'output_stream': 'stderr',
  \})

Execute (PreProcess should accept a 'both' output_stream):
  call ale#linter#PreProcess({
  \ 'name': 'foo',
  \ 'callback': 'SomeFunction',
  \ 'executable': 'echo',
  \ 'command': 'echo',
  \ 'output_stream': 'both',
  \})

Execute(PreProcess should complain if the command_chain is not a List):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': 'x',
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual '`command_chain` must be a List', g:vader_exception

Execute(PreProcess should complain if the command_chain is empty):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [],
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual '`command_chain` must contain at least one item', g:vader_exception

Execute(PreProcess should complain if the command_chain has no callback):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{}],
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'The `command_chain` item 0 must define a `callback` function', g:vader_exception

Execute(PreProcess should complain if the command_chain callback is not a function):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{'callback': 2}],
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'The `command_chain` item 0 must define a `callback` function', g:vader_exception

Execute(PreProcess should accept a chain with one callback):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{'callback': 'foo'}],
  \}
  call ale#linter#PreProcess(g:linter)

Execute(PreProcess should complain about invalid output_stream values in the chain):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{'callback': 'foo', 'output_stream': ''}],
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual "The `command_chain` item 0 `output_stream` flag must be 'stdout', 'stderr', or 'both'", g:vader_exception

Execute(PreProcess should complain about valid output_stream values in the chain):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{'callback': 'foo', 'output_stream': 'stdout'}],
  \}
  call ale#linter#PreProcess(g:linter)
  let g:linter.command_chain[0].output_stream = 'stderr'
  call ale#linter#PreProcess(g:linter)
  let g:linter.command_chain[0].output_stream = 'both'
  call ale#linter#PreProcess(g:linter)

Execute(PreProcess should complain about invalid chain items at higher indices):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{'callback': 'foo'}, {'callback': 123}],
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'The `command_chain` item 1 must define a `callback` function', g:vader_exception

Execute(PreProcess should complain when conflicting command options are used):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command': 'foo',
  \ 'command_chain': [{'callback': 'foo'}],
  \}
  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'Only one of `command`, `command_callback`, or `command_chain` should be set', g:vader_exception

  unlet g:linter.command
  let g:linter.command_callback = 'foo'

  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'Only one of `command`, `command_callback`, or `command_chain` should be set', g:vader_exception

  let g:linter.command = 'foo'
  unlet g:linter.command_chain

  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'Only one of `command`, `command_callback`, or `command_chain` should be set', g:vader_exception

Execute(PreProcess should process the read_buffer option correctly):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command_chain': [{'callback': 'foo'}, {'callback': 'bar'}],
  \ 'read_buffer': '0',
  \}

  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual '`read_buffer` must be `0` or `1`', g:vader_exception

  let g:linter.read_buffer = 0

  call ale#linter#PreProcess(g:linter)

  let g:linter.read_buffer = 1

  call ale#linter#PreProcess(g:linter)

  unlet g:linter.read_buffer
  let g:linter.command_chain[0].read_buffer = '0'

  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'The `command_chain` item 0 value for `read_buffer` must be `0` or `1`', g:vader_exception

  let g:linter.command_chain[0].read_buffer = 0

  call ale#linter#PreProcess(g:linter)

  let g:linter.command_chain[1].read_buffer = '0'

  AssertThrows call ale#linter#PreProcess(g:linter)
  AssertEqual 'The `command_chain` item 1 value for `read_buffer` must be `0` or `1`', g:vader_exception

  let g:linter.command_chain[1].read_buffer = 1

  call ale#linter#PreProcess(g:linter)

Execute(PreProcess should set a default value for read_buffer):
  let g:linter = {
  \ 'name': 'x',
  \ 'callback': 'x',
  \ 'executable': 'x',
  \ 'command': 'x',
  \}

  AssertEqual ale#linter#PreProcess(g:linter).read_buffer, 1