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Aggregating Failures

RSpec::Expectations provides aggregate_failures, an API that allows you to group a set of expectations and see all the failures at once, rather than it aborting on the first failure. RSpec::Core improves on this feature in a couple of ways:

  • RSpec::Core provides much better failure output, adding code snippets and backtraces to the sub-failures, just like it does for any normal failure.
  • RSpec::Core provides metadata integration for this feature. Each example that is tagged with :aggregate_failures will be wrapped in an aggregate_failures block. You can also use config.define_derived_metadata to apply this to every example automatically.

The metadata form is quite convenient, but may not work well for end-to-end tests that have multiple distinct steps. For example, consider a spec for an HTTP client workflow that (1) makes a request, (2) expects a redirect, (3) follows the redirect, and (4) expects a particular response. You probably want the expect(response.status).to be_between(300, 399) expectation to immediately abort if it fails, because you can't perform the next step (following the redirect) if that is not satisfied. For these situations, we encourage you to use the aggregate_failures block form to wrap each set of expectations that represents a distinct step in the test workflow.

Background

Given a file named "lib/client.rb" with:

Response = Struct.new(:status, :headers, :body)

class Client
def self.make_request(url='/')
Response.new(404, { "Content-Type" => "text/plain" }, "Not Found")
end
end

Use aggregate_failures block form

Given a file named "spec/use_block_form_spec.rb" with:

require 'client'

RSpec.describe Client do
after do
# this should be appended to failure list
expect(false).to be(true), "after hook failure"
end

around do |ex|
ex.run
# this should also be appended to failure list
expect(false).to be(true), "around hook failure"
end

it "returns a successful response" do
response = Client.make_request

aggregate_failures "testing response" do
expect(response.status).to eq(200)
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.body).to eq('{"message":"Success"}')
end
end
end

When I run rspec spec/use_block_form_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client returns a successful response
Got 3 failures:

1.1) Got 3 failures from failure aggregation block "testing response".
# ./spec/use_block_form_spec.rb:18
# ./spec/use_block_form_spec.rb:10

1.1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/use_block_form_spec.rb:19

1.1.2) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1 +1 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/use_block_form_spec.rb:20

1.1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/use_block_form_spec.rb:21

1.2) Failure/Error: expect(false).to be(true), "after hook failure"
after hook failure
# ./spec/use_block_form_spec.rb:6
# ./spec/use_block_form_spec.rb:10

1.3) Failure/Error: expect(false).to be(true), "around hook failure"
around hook failure
# ./spec/use_block_form_spec.rb:12

Use aggregate_failures block form

Given a file named "spec/use_block_form_spec.rb" with:

require 'client'

RSpec.describe Client do
after do
# this should be appended to failure list
expect(false).to be(true), "after hook failure"
end

around do |ex|
ex.run
# this should also be appended to failure list
expect(false).to be(true), "around hook failure"
end

it "returns a successful response" do
response = Client.make_request

aggregate_failures "testing response" do
expect(response.status).to eq(200)
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.body).to eq('{"message":"Success"}')
end
end
end

When I run rspec spec/use_block_form_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client returns a successful response
Got 3 failures:

1.1) Got 3 failures from failure aggregation block "testing response".
# ./spec/use_block_form_spec.rb:18
# ./spec/use_block_form_spec.rb:10

1.1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/use_block_form_spec.rb:19

1.1.2) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1,2 +1,2 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/use_block_form_spec.rb:20

1.1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/use_block_form_spec.rb:21

1.2) Failure/Error: expect(false).to be(true), "after hook failure"
after hook failure
# ./spec/use_block_form_spec.rb:6
# ./spec/use_block_form_spec.rb:10

1.3) Failure/Error: expect(false).to be(true), "around hook failure"
around hook failure
# ./spec/use_block_form_spec.rb:12

Use :aggregate_failures metadata

Given a file named "spec/use_metadata_spec.rb" with:

require 'client'

RSpec.describe Client do
it "follows a redirect", :aggregate_failures do
response = Client.make_request

expect(response.status).to eq(302)
expect(response.body).to eq('{"message":"Redirect"}')

redirect_response = Client.make_request(response.headers.fetch('Location'))

expect(redirect_response.status).to eq(200)
expect(redirect_response.body).to eq('{"message":"OK"}')
end
end

When I run rspec spec/use_metadata_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client follows a redirect
Got 2 failures and 1 other error:

1.1) Failure/Error: expect(response.status).to eq(302)

expected: 302
got: 404

(compared using ==)
# ./spec/use_metadata_spec.rb:7

1.2) Failure/Error: expect(response.body).to eq('{"message":"Redirect"}')

expected: "{\"message\":\"Redirect\"}"
got: "Not Found"

(compared using ==)
# ./spec/use_metadata_spec.rb:8

1.3) Failure/Error: redirect_response = Client.make_request(response.headers.fetch('Location'))
KeyError:
key not found: "Location"
# ./spec/use_metadata_spec.rb:10
# ./spec/use_metadata_spec.rb:10

Enable failure aggregation globally using define_derived_metadata

Given a file named "spec/enable_globally_spec.rb" with:

require 'client'

RSpec.configure do |c|
c.define_derived_metadata do |meta|
meta[:aggregate_failures] = true
end
end

RSpec.describe Client do
it "returns a successful response" do
response = Client.make_request

expect(response.status).to eq(200)
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.body).to eq('{"message":"Success"}')
end
end

When I run rspec spec/enable_globally_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client returns a successful response
Got 3 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/enable_globally_spec.rb:13

1.2) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1 +1 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/enable_globally_spec.rb:14

1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/enable_globally_spec.rb:15

Enable failure aggregation globally using define_derived_metadata

Given a file named "spec/enable_globally_spec.rb" with:

require 'client'

RSpec.configure do |c|
c.define_derived_metadata do |meta|
meta[:aggregate_failures] = true
end
end

RSpec.describe Client do
it "returns a successful response" do
response = Client.make_request

expect(response.status).to eq(200)
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.body).to eq('{"message":"Success"}')
end
end

When I run rspec spec/enable_globally_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client returns a successful response
Got 3 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/enable_globally_spec.rb:13

1.2) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1,2 +1,2 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/enable_globally_spec.rb:14

1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/enable_globally_spec.rb:15

Nested failure aggregation works

Given a file named "spec/nested_failure_aggregation_spec.rb" with:

require 'client'

RSpec.describe Client do
it "returns a successful response", :aggregate_failures do
response = Client.make_request

expect(response.status).to eq(200)

aggregate_failures "testing headers" do
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.headers).to include("Content-Length" => "21")
end

expect(response.body).to eq('{"message":"Success"}')
end
end

When I run rspec spec/nested_failure_aggregation_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client returns a successful response
Got 3 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/nested_failure_aggregation_spec.rb:7

1.2) Got 2 failures from failure aggregation block "testing headers".
# ./spec/nested_failure_aggregation_spec.rb:9

1.2.1) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1 +1 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/nested_failure_aggregation_spec.rb:10

1.2.2) Failure/Error: expect(response.headers).to include("Content-Length" => "21")
expected {"Content-Type" => "text/plain"} to include {"Content-Length" => "21"}
Diff:
@@ -1 +1 @@
-"Content-Length" => "21",
+"Content-Type" => "text/plain",
# ./spec/nested_failure_aggregation_spec.rb:11

1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/nested_failure_aggregation_spec.rb:14

Nested failure aggregation works

Given a file named "spec/nested_failure_aggregation_spec.rb" with:

require 'client'

RSpec.describe Client do
it "returns a successful response", :aggregate_failures do
response = Client.make_request

expect(response.status).to eq(200)

aggregate_failures "testing headers" do
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.headers).to include("Content-Length" => "21")
end

expect(response.body).to eq('{"message":"Success"}')
end
end

When I run rspec spec/nested_failure_aggregation_spec.rb

Then it should fail and list all the failures:

Failures:

1) Client returns a successful response
Got 3 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/nested_failure_aggregation_spec.rb:7

1.2) Got 2 failures from failure aggregation block "testing headers".
# ./spec/nested_failure_aggregation_spec.rb:9

1.2.1) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1,2 +1,2 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/nested_failure_aggregation_spec.rb:10

1.2.2) Failure/Error: expect(response.headers).to include("Content-Length" => "21")
expected {"Content-Type" => "text/plain"} to include {"Content-Length" => "21"}
Diff:
@@ -1,2 +1,2 @@
-"Content-Length" => "21",
+"Content-Type" => "text/plain",
# ./spec/nested_failure_aggregation_spec.rb:11

1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/nested_failure_aggregation_spec.rb:14

Mock expectation failures are aggregated as well

Given a file named "spec/mock_expectation_failure_spec.rb" with:

require 'client'

RSpec.describe "Aggregating Failures", :aggregate_failures do
it "has a normal expectation failure and a message expectation failure" do
client = double("Client")
expect(client).to receive(:put).with("updated data")
allow(client).to receive(:get).and_return(Response.new(404, {}, "Not Found"))

response = client.get
expect(response.status).to eq(200)
end
end

When I run rspec spec/mock_expectation_failure_spec.rb

Then it should fail and list all the failures:

Failures:

1) Aggregating Failures has a normal expectation failure and a message expectation failure
Got 2 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/mock_expectation_failure_spec.rb:10

1.2) Failure/Error: expect(client).to receive(:put).with("updated data")
(Double "Client").put("updated data")
expected: 1 time with arguments: ("updated data")
received: 0 times
# ./spec/mock_expectation_failure_spec.rb:6

Pending integrates properly with aggregated failures

Given a file named "spec/pending_spec.rb" with:

require 'client'

RSpec.describe Client do
it "returns a successful response", :aggregate_failures do
pending "Not yet ready"
response = Client.make_request

expect(response.status).to eq(200)
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.body).to eq('{"message":"Success"}')
end
end

When I run rspec spec/pending_spec.rb

Then it should pass and list all the pending examples:

Pending: (Failures listed here are expected and do not affect your suite's status)

1) Client returns a successful response
# Not yet ready
Got 3 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/pending_spec.rb:8

1.2) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1 +1 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/pending_spec.rb:9

1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/pending_spec.rb:10

Pending integrates properly with aggregated failures

Given a file named "spec/pending_spec.rb" with:

require 'client'

RSpec.describe Client do
it "returns a successful response", :aggregate_failures do
pending "Not yet ready"
response = Client.make_request

expect(response.status).to eq(200)
expect(response.headers).to include("Content-Type" => "application/json")
expect(response.body).to eq('{"message":"Success"}')
end
end

When I run rspec spec/pending_spec.rb

Then it should pass and list all the pending examples:

Pending: (Failures listed here are expected and do not affect your suite's status)

1) Client returns a successful response
# Not yet ready
Got 3 failures:

1.1) Failure/Error: expect(response.status).to eq(200)

expected: 200
got: 404

(compared using ==)
# ./spec/pending_spec.rb:8

1.2) Failure/Error: expect(response.headers).to include("Content-Type" => "application/json")
expected {"Content-Type" => "text/plain"} to include {"Content-Type" => "application/json"}
Diff:
@@ -1,2 +1,2 @@
-"Content-Type" => "application/json",
+"Content-Type" => "text/plain",
# ./spec/pending_spec.rb:9

1.3) Failure/Error: expect(response.body).to eq('{"message":"Success"}')

expected: "{\"message\":\"Success\"}"
got: "Not Found"

(compared using ==)
# ./spec/pending_spec.rb:10