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RSpec.shared_examples "output_to_stream" do |stream_name, matcher_method, helper_module|
include helper_module
extend helper_module
it_behaves_like "an RSpec block-only matcher" do
let(:matcher) { output(/fo/).send(matcher_method) }
def valid_block
print_to_stream('foo')
end
def invalid_block
end
end
define_method :matcher do |*args|
output(args.first).send(matcher_method)
end
it 'is diffable' do
expect(matcher).to be_diffable
end
it 'does not produce warnings when the failure message is accessed first' do
expect($VERBOSE).to be_truthy
expect { matcher.failure_message }.not_to output.to_stderr
end
context "expect { ... }.to output.#{matcher_method}" do
it "passes if the block outputs to #{stream_name}" do
expect { print_to_stream 'foo' }.to matcher
end
it "fails if the block does not output to #{stream_name}" do
expect {
expect {}.to matcher
}.to fail_with("expected block to output to #{stream_name}, but did not")
end
end
context "expect { ... }.not_to output.#{matcher_method}" do
it "passes if the block does not output to #{stream_name}" do
expect {}.not_to matcher
end
it "fails if the block outputs to #{stream_name}" do
expect {
expect { print_to_stream 'foo' }.not_to matcher
}.to fail_with("expected block to not output to #{stream_name}, but output \"foo\"")
end
end
context "expect { ... }.to output('string').#{matcher_method}" do
it "passes if the block outputs that string to #{stream_name}" do
expect { print_to_stream 'foo' }.to matcher("foo")
end
it "fails if the block does not output to #{stream_name}" do
expect {
expect {}.to matcher('foo')
}.to fail_with("expected block to output \"foo\" to #{stream_name}, but output nothing")
end
it "fails if the block outputs a different string to #{stream_name}" do
expect {
expect { print_to_stream 'food' }.to matcher('foo')
}.to fail_with("expected block to output \"foo\" to #{stream_name}, but output \"food\"")
end
end
context "expect { ... }.to_not output('string').#{matcher_method}" do
it "passes if the block outputs a different string to #{stream_name}" do
expect { print_to_stream 'food' }.to_not matcher('foo')
end
it "passes if the block does not output to #{stream_name}" do
expect {}.to_not matcher('foo')
end
it "fails if the block outputs the same string to #{stream_name}" do
expect {
expect { print_to_stream 'foo' }.to_not matcher('foo')
}.to fail_with("expected block to not output \"foo\" to #{stream_name}, but output \"foo\"")
end
end
context "expect { ... }.to output(/regex/).#{matcher_method}" do
it "passes if the block outputs a string to #{stream_name} that matches the regex" do
expect { print_to_stream 'foo' }.to matcher(/foo/)
end
it "fails if the block does not output to #{stream_name}" do
expect {
expect {}.to matcher(/foo/)
}.to fail_including("expected block to output /foo/ to #{stream_name}, but output nothing\nDiff")
end
it "fails if the block outputs a string to #{stream_name} that does not match" do
expect {
expect { print_to_stream 'foo' }.to matcher(/food/)
}.to fail_including("expected block to output /food/ to #{stream_name}, but output \"foo\"\nDiff")
end
end
context "expect { ... }.to_not output(/regex/).#{matcher_method}" do
it "passes if the block outputs a string to #{stream_name} that does not match the regex" do
expect { print_to_stream 'food' }.to_not matcher(/bar/)
end
it "passes if the block does not output to #{stream_name}" do
expect {}.to_not matcher(/foo/)
end
it "fails if the block outputs a string to #{stream_name} that matches the regex" do
expect {
expect { print_to_stream 'foo' }.to_not matcher(/foo/)
}.to fail_including("expected block to not output /foo/ to #{stream_name}, but output \"foo\"\nDiff")
end
end
context "expect { ... }.to output(matcher).#{matcher_method}" do
it "passes if the block outputs a string to #{stream_name} that passes the given matcher" do
expect { print_to_stream 'foo' }.to matcher(a_string_starting_with("f"))
end
it "fails if the block outputs a string to #{stream_name} that does not pass the given matcher" do
expect {
expect { print_to_stream 'foo' }.to matcher(a_string_starting_with("b"))
}.to fail_including("expected block to output a string starting with \"b\" to #{stream_name}, but output \"foo\"\nDiff")
end
end
context "expect { ... }.to_not output(matcher).#{matcher_method}" do
it "passes if the block does not output a string to #{stream_name} that passes the given matcher" do
expect { print_to_stream 'foo' }.to_not matcher(a_string_starting_with("b"))
end
it "fails if the block outputs a string to #{stream_name} that passes the given matcher" do
expect {
expect { print_to_stream 'foo' }.to_not matcher(a_string_starting_with("f"))
}.to fail_including("expected block to not output a string starting with \"f\" to #{stream_name}, but output \"foo\"\nDiff")
end
end
end
module RSpec
module Matchers
RSpec.describe "output.to_stderr matcher" do
include_examples "output_to_stream", :stderr, :to_stderr, Module.new {
def print_to_stream(msg)
$stderr.print(msg)
end
}
end
RSpec.describe "output.to_stdout matcher" do
include_examples "output_to_stream", :stdout, :to_stdout, Module.new {
def print_to_stream(msg)
print(msg)
end
}
end
RSpec.describe "output.to_stderr_from_any_process matcher" do
include_examples "output_to_stream", :stderr, :to_stderr_from_any_process, Module.new {
def print_to_stream(msg)
if RSpec::Support::OS.windows?
system("<nul set /p msg=\"#{msg}\" 1>&2")
else
system("printf #{msg} 1>&2")
end
end
}
end
RSpec.describe "output.to_stdout_from_any_process matcher" do
include_examples "output_to_stream", :stdout, :to_stdout_from_any_process, Module.new {
def print_to_stream(msg)
if RSpec::Support::OS.windows?
system("<nul set /p msg=#{msg}")
else
system("printf #{msg}")
end
end
}
end
RSpec.describe "output (without `to_stdout` or `to_stderr`)" do
it 'raises an error explaining the use is invalid' do
expect {
expect { print 'foo' }.to output
}.to raise_error(/must chain.*to_stdout.*to_stderr/)
end
it 'still provides a description (e.g. when used in a one-liner)' do
expect(output("foo").description).to eq('output "foo" to some stream')
end
end
RSpec.describe "can capture stdin and stderr" do
it "prints diff for both when both fail" do
expect {
expect {
print "foo"; $stderr.print("bar")
}.to output(/baz/).to_stdout.and output(/qux/).to_stderr
}.to fail_including(
'expected block to output /baz/ to stdout, but output "foo"',
'...and:',
'expected block to output /qux/ to stderr, but output "bar"',
'Diff for (output /baz/ to stdout):',
'-/baz/',
'+"foo"',
'Diff for (output /qux/ to stderr):',
'-/qux/',
'+"bar"'
)
end
end
end
end
|
