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Project: RSpec Core 3.12

Publisher: RSpec

Profile examples

The --profile command line option (available from RSpec.configure as
#profile_examples), when set, will cause RSpec to dump out a list of your
slowest examples. By default, it prints the 10 slowest examples, but you can
set it to a different value to have it print more or fewer slow examples. If
--fail-fast option is used together with --profile and there is a failure,
slow examples are not shown.

Background
Given
a file named "spec/spec_helper.rb" with:
And
a file named "spec/example_spec.rb" with: 
require "spec_helper"

RSpec.describe "something" do
  it "sleeps for 0.1 seconds (example 1)" do
    sleep 0.1
    expect(1).to eq(1)
  end

  it "sleeps for 0 seconds (example 2)" do
    expect(2).to eq(2)
  end

  it "sleeps for 0.15 seconds (example 3)" do
    sleep 0.15
    expect(3).to eq(3)
  end

  it "sleeps for 0.05 seconds (example 4)" do
    sleep 0.05
    expect(4).to eq(4)
  end

  it "sleeps for 0.05 seconds (example 5)" do
    sleep 0.05
    expect(5).to eq(5)
  end

  it "sleeps for 0.05 seconds (example 6)" do
    sleep 0.05
    expect(6).to eq(6)
  end

  it "sleeps for 0.05 seconds (example 7)" do
    sleep 0.05
    expect(7).to eq(7)
  end

  it "sleeps for 0.05 seconds (example 8)" do
    sleep 0.05
    expect(8).to eq(8)
  end

  it "sleeps for 0.05 seconds (example 9)" do
    sleep 0.05
    expect(9).to eq(9)
  end

  it "sleeps for 0.05 seconds (example 10)" do
    sleep 0.05
    expect(10).to eq(10)
  end

  it "sleeps for 0.05 seconds (example 11)" do
    sleep 0.05
    expect(11).to eq(11)
  end
end
Scenarios
  1. By default does not show profile
  2. Setting `profile_examples` to true shows 10 examples
  3. Setting `profile_examples` to 2 shows 2 examples
  4. Setting profile examples through CLI using `--profile`
  5. Using `--no-profile` overrules config options
  6. Using `--profile` with `--fail-fast` shows slow examples if everything passes
  7. Using `--profile` shows slow examples even in case of failures
  8. Using `--profile` with `--fail-fast` doesn't show slow examples in case of failures
  9. Using `--profile` with slow before hooks includes hook execution time
By default does not show profile
When
I run rspec spec
Then
the examples should all pass
And
the output should not contain "example 1"
And
the output should not contain "example 2"
And
the output should not contain "example 3"
And
the output should not contain "example 4"
And
the output should not contain "example 5"
And
the output should not contain "example 6"
And
the output should not contain "example 7"
And
the output should not contain "example 8"
And
the output should not contain "example 9"
And
the output should not contain "example 10"
And
the output should not contain "example 11"
Setting `profile_examples` to true shows 10 examples
Given
a file named "spec/spec_helper.rb" with: 
RSpec.configure { |c| c.profile_examples = true }
When
I run rspec spec
Then
the examples should all pass
And
the output should contain "Top 10 slowest examples"
And
the output should contain "example 1"
And
the output should not contain "example 2"
And
the output should contain "example 3"
And
the output should contain "example 4"
And
the output should contain "example 5"
And
the output should contain "example 6"
And
the output should contain "example 7"
And
the output should contain "example 8"
And
the output should contain "example 9"
And
the output should contain "example 10"
And
the output should contain "example 11"
Setting `profile_examples` to 2 shows 2 examples
Given
a file named "spec/spec_helper.rb" with: 
RSpec.configure { |c| c.profile_examples = 2 }
When
I run rspec spec
Then
the examples should all pass
And
the output should contain "Top 2 slowest examples"
And
the output should contain "example 1"
And
the output should not contain "example 2"
And
the output should contain "example 3"
And
the output should not contain "example 4"
And
the output should not contain "example 5"
And
the output should not contain "example 6"
And
the output should not contain "example 7"
And
the output should not contain "example 8"
And
the output should not contain "example 9"
And
the output should not contain "example 10"
And
the output should not contain "example 11"
Setting profile examples through CLI using `--profile`
When
I run rspec spec --profile 2
Then
the examples should all pass
And
the output should contain "Top 2 slowest examples"
And
the output should contain "example 1"
And
the output should not contain "example 2"
And
the output should contain "example 3"
And
the output should not contain "example 4"
And
the output should not contain "example 5"
And
the output should not contain "example 6"
And
the output should not contain "example 7"
And
the output should not contain "example 8"
And
the output should not contain "example 9"
And
the output should not contain "example 10"
And
the output should not contain "example 11"
Using `--no-profile` overrules config options
Given
a file named "spec/spec_helper.rb" with: 
RSpec.configure { |c| c.profile_examples = true }
When
I run rspec spec --no-profile
Then
the examples should all pass
And
the output should not contain "example 1"
And
the output should not contain "example 2"
And
the output should not contain "example 3"
And
the output should not contain "example 4"
And
the output should not contain "example 5"
And
the output should not contain "example 6"
And
the output should not contain "example 7"
And
the output should not contain "example 8"
And
the output should not contain "example 9"
And
the output should not contain "example 10"
And
the output should not contain "example 11"
Using `--profile` with `--fail-fast` shows slow examples if everything passes
When
I run rspec spec --fail-fast --profile
Then
the examples should all pass
And
the output should contain "Top 10 slowest examples"
And
the output should contain "example 1"
And
the output should not contain "example 2"
And
the output should contain "example 3"
And
the output should contain "example 4"
And
the output should contain "example 5"
And
the output should contain "example 6"
And
the output should contain "example 7"
And
the output should contain "example 8"
And
the output should contain "example 9"
And
the output should contain "example 10"
And
the output should contain "example 11"
Using `--profile` shows slow examples even in case of failures
Given
a file named "spec/example_spec.rb" with: 
require "spec_helper"

RSpec.describe "something" do
  it "sleeps for 0.1 seconds (example 1)" do
    sleep 0.1
    expect(1).to eq(1)
  end

  it "fails" do
    fail
  end
end
When
I run rspec spec --profile
Then
the output should contain "2 examples, 1 failure"
And
the output should contain "Top 2 slowest examples"
And
the output should contain "example 1"
Using `--profile` with `--fail-fast` doesn't show slow examples in case of failures
Given
a file named "spec/example_spec.rb" with: 
require "spec_helper"

RSpec.describe "something" do
  it "sleeps for 0.1 seconds (example 1)" do
    sleep 0.1
    expect(1).to eq(1)
  end

  it "fails" do
    fail
  end
end
When
I run rspec spec --fail-fast --profile
Then
the output should not contain "Top 2 slowest examples"
And
the output should not contain "example 1"
Using `--profile` with slow before hooks includes hook execution time
Given
a file named "spec/example_spec.rb" with: 
RSpec.describe "slow before context hook" do
  before(:context) do
    sleep 0.2
  end

  context "nested" do
    it "example" do
      expect(10).to eq(10)
    end
  end
end

RSpec.describe "slow example" do
  it "slow example" do
    sleep 0.1
    expect(10).to eq(10)
  end
end
When
I run rspec spec --profile 1
Then
the output should report "slow before context hook" as the slowest example group

Last published 4 months ago by Jon Rowe.