Improve implicit description for RSpec::Rails::Matchers::ActionCable:…

…:HaveBroadcastedTo

Previously, tests defined like this:

```rb
it do
  expect { some_action }.to have_broadcasted_to("stream_name").from_channel(SomeChannel).with("some_data")
end
```

would implicitly be given the description `have broadcasted to`, which is derived from the name of the matcher method.
This didn't carry any extra information about the data we're expecting to be broadcast from the channel - behaviour
which would be very welcome in combination with Turbo Streams. With a matcher for Turbo Streams, we might benefit from
a description like "broadcast exactly 1 messages to stream with turbo-stream[action="append"][target="some_list"]".

lib/rspec/rails/matchers/action_cable.rb

@@ -50,7 +50,13 @@ def have_broadcasted_to(target = nil)
 
         ActionCable::HaveBroadcastedTo.new(target, channel: described_class)
       end
-      alias_method :broadcast_to, :have_broadcasted_to
+
+      def broadcast_to(target = nil)
+        RSpec::Matchers::AliasedMatcher.new(
+          have_broadcasted_to(target),
+          ->(old_desc) { old_desc.gsub("have broadcasted", "broadcast") }
+        )
+      end
 
     private
 

lib/rspec/rails/matchers/action_cable/have_broadcasted_to.rb

@@ -51,6 +51,10 @@ def thrice
             exactly(:thrice)
           end
 
+          def description
+            "have broadcasted #{base_description}"
+          end
+
           def failure_message
             "expected to broadcast #{base_message}".tap do |msg|
               if @unmatching_msgs.any?
@@ -140,9 +144,14 @@ def set_expected_number(relativity, count)
               end
           end
 
-          def base_message
+          def base_description
             "#{message_expectation_modifier} #{@expected_number} messages to #{stream}".tap do |msg|
               msg << " with #{data_description(@data)}" unless @data.nil?
+            end
+          end
+
+          def base_message
+            base_description.tap do |msg|
               msg << ", but broadcast #{@matching_msgs_count}"
             end
           end
@@ -151,7 +160,7 @@ def data_description(data)
             if data.is_a?(RSpec::Matchers::Composable)
               data.description
             else
-              data
+              data.inspect
             end
           end
 

spec/rspec/rails/matchers/action_cable/have_broadcasted_to_spec.rb

@@ -226,5 +226,46 @@ def broadcast(stream, msg)
         end
       end
     end
+
+    it "has a description when not chained" do
+      expect(have_broadcasted_to("stream").description).to eq("have broadcasted exactly 1 messages to stream")
+    end
+
+    it "has a description when not chained and aliased" do
+      expect(broadcast_to("stream").description).to eq("broadcast exactly 1 messages to stream")
+    end
+
+    it "has a description when stream name is passed as an array" do
+      expect(have_broadcasted_to(%w[stream stream_2]).from_channel(channel).description).to eq("have broadcasted exactly 1 messages to broadcast:stream:stream_2")
+    end
+
+    it "has a description when stream name is passed as an array and aliased" do
+      expect(broadcast_to(%w[stream stream_2]).from_channel(channel).description).to eq("broadcast exactly 1 messages to broadcast:stream:stream_2")
+    end
+
+    it "has a description when chained with `from_channel" do
+      # We don't include the channel in the failure message, so we don't include it in the description either.
+      expect(have_broadcasted_to("stream").from_channel(channel).description).to eq("have broadcasted exactly 1 messages to stream")
+    end
+
+    it "has a description when chained with `from_channel" do
+      # We don't include the channel in the failure message, so we don't include it in the description either.
+      expect(have_broadcasted_to("stream").from_channel(channel).description).to eq("have broadcasted exactly 1 messages to stream")
+    end
+
+    it "has a description when chained with `with`" do
+      # We don't include the channel in the failure message, so we don't include it in the description either.
+      expect(have_broadcasted_to("stream").from_channel(channel).with("hello world").description).to eq("have broadcasted exactly 1 messages to stream with \"hello world\"")
+    end
+
+    it "has a description when chained with `with` and a composable matcher" do
+      # We don't include the channel in the failure message, so we don't include it in the description either.
+      expect(
+        have_broadcasted_to("stream")
+          .from_channel(channel)
+          .with(a_hash_including(a: :b))
+          .description
+      ).to eq("have broadcasted exactly 1 messages to stream with a hash including {:a => :b}")
+    end
   end
 end