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Project: RSpec Core 3.1

Publisher: RSpec

Excluding lines from the backtrace

To reduce the noise when diagnosing failures, RSpec excludes matching lines
from backtraces. The default exclusion patterns are:

/\/lib\d*\/ruby\//,
/org\/jruby\//,
/bin\//,
/lib\/rspec\/(core|expectations|matchers|mocks)/

This list can be modified or replaced with the backtrace_exclusion_patterns
option. Additionally, rspec can be run with the --backtrace option to skip
backtrace cleaning entirely.

In addition, if you want to filter out backtrace lines from specific gems, you
can use config.filter_gems_from_backtrace.

Scenarios
  1. Using default `backtrace_exclusion_patterns`
  2. Replacing `backtrace_exclusion_patterns`
  3. Appending to `backtrace_exclusion_patterns`
  4. Running `rspec` with the `--backtrace` option
  5. Using `filter_gems_from_backtrace` to filter the named gem
Using default `backtrace_exclusion_patterns`
Given
a file named "spec/failing_spec.rb" with: 
RSpec.describe "2 + 2" do
  it "is 5" do
    expect(2+2).to eq(5)
  end
end
When
I run rspec
Then
the output should contain "1 example, 1 failure"
And
the output should not contain "lib/rspec/expectations"
Replacing `backtrace_exclusion_patterns`
Given
a file named "spec/spec_helper.rb" with: 
RSpec.configure do |config|
  config.backtrace_exclusion_patterns = [
    /spec_helper/
  ]
end

def foo
  "bar"
end
And
a file named "spec/example_spec.rb" with: 
require 'spec_helper'
RSpec.describe "foo" do
  it "returns baz" do
    expect(foo).to eq("baz")
  end
end
When
I run rspec
Then
the output should contain "1 example, 1 failure"
And
the output should contain "lib/rspec/expectations"
Appending to `backtrace_exclusion_patterns`
Given
a file named "spec/matchers/be_baz_matcher.rb" with: 
RSpec::Matchers.define :be_baz do |_|
  match do |actual|
    actual == "baz"
  end
end
And
a file named "spec/example_spec.rb" with: 
RSpec.configure do |config|
  config.backtrace_exclusion_patterns << /be_baz_matcher/
end

RSpec.describe "bar" do
  it "is baz" do
    expect("bar").to be_baz
  end
end
When
I run rspec
Then
the output should contain "1 example, 1 failure"
But
the output should not contain "be_baz_matcher"
And
the output should not contain "lib/rspec/expectations"
Running `rspec` with the `--backtrace` option
Given
a file named "spec/matchers/be_baz_matcher.rb" with: 
RSpec::Matchers.define :be_baz do |_|
  match do |actual|
    actual == "baz"
  end
end
And
a file named "spec/example_spec.rb" with: 
RSpec.configure do |config|
  config.backtrace_exclusion_patterns << /be_baz_matcher/
end

RSpec.describe "bar" do
  it "is baz" do
    expect("bar").to be_baz
  end
end
When
I run rspec --backtrace
Then
the output should contain "1 example, 1 failure"
And
the output should not contain "be_baz_matcher"
Using `filter_gems_from_backtrace` to filter the named gem
Given
a vendored gem named "my_gem" containing a file named "lib/my_gem.rb" with: 
class MyGem
  def self.do_amazing_things!
    # intentional bug to trigger an exception
    impossible_math = 10 / 0
    "10 div 0 is: #{impossible_math}"
  end
end
And
a file named "spec/use_my_gem_spec.rb" with: 
require 'my_gem'

RSpec.describe "Using my_gem" do
  it 'does amazing things' do
    expect(MyGem.do_amazing_things!).to include("10 div 0 is")
  end
end
And
a file named "spec/spec_helper.rb" with: 
RSpec.configure do |config|
  config.filter_gems_from_backtrace "my_gem"
end
Then
the output from rspec should contain "# ./vendor/my_gem-1.2.3/lib/my_gem.rb:4:in `do_amazing_things!'"
But
the output from rspec --require spec_helper should not contain "# ./vendor/my_gem-1.2.3/lib/my_gem.rb:4:in `do_amazing_things!'"

Last published over 5 years ago by myronmarston.