--example option

Use the --example (or -e) option to filter examples by name.

The argument is matched against the full description of the example, which is the concatenation of descriptions of the group (including any nested groups) and the example.

This allows you to run a single uniquely named example, all examples with similar names, all the examples in a uniquely named group, etc, etc.

You can also use the option more than once to specify multiple example matches.

Note: description-less examples that have generated descriptions (typical when using the one-liner syntax) cannot be directly filtered with this option, because it is necessary to execute the example to generate the description, so RSpec is unable to use the not-yet-generated description to decide whether or not to execute an example. You can, of course, pass part of a group’s description to select all examples defined in the group (including those that have no description).

Background

Given a file named “first_spec.rb” with:

RSpec.describe "first group" do
  it "first example in first group" do; end
  it "second example in first group" do; end
end

And a file named “second_spec.rb” with:

RSpec.describe "second group" do
  it "first example in second group" do; end
  it "second example in second group" do; end
end

And a file named “third_spec.rb” with:

RSpec.describe "third group" do
  it "first example in third group" do; end
  context "nested group" do
    it "first example in nested group" do; end
    it "second example in nested group" do; end
  end
end

And a file named “fourth_spec.rb” with:

RSpec.describe Array do
  describe "#length" do
    it "is the number of items" do
      expect(Array.new([1,2,3]).length).to eq 3
    end
  end
end

No matches

When I run rspec . --example nothing_like_this

Then the process should succeed even though no examples were run.

Match on one word

When I run rspec . --example example

Then the examples should all pass.

One match in each context

When I run rspec . --example 'first example'

Then the examples should all pass.

One match in one file using just the example name

When I run rspec . --example 'first example in first group'

Then the examples should all pass.

One match in one file using the example name and the group name

When I run rspec . --example 'first group first example in first group'

Then the examples should all pass.

All examples in one group

When I run rspec . --example 'first group'

Then the examples should all pass.

One match in one file with group name

When I run rspec . --example 'second group first example'

Then the examples should all pass.

All examples in one group including examples in nested groups

When I run rspec . --example 'third group'

Then the examples should all pass.

Match using ClassName#method_name form

When I run rspec . --example 'Array#length'

Then the examples should all pass.

Multiple applications of example name option

When I run rspec . --example 'first group' --example 'second group' --format d

Then the examples should all pass

And the output should contain all of these:

And the output should not contain any of these: