Add RSpec all matchers spec

spec/rspec/expectations/all_matcher_spec.cr

@@ -0,0 +1,39 @@
+require "../../spec_helper"
+
+# Examples taken from:
+# https://relishapp.com/rspec/rspec-expectations/v/3-8/docs/built-in-matchers/all-matcher
+# and modified to fit Spectator and Crystal.
+Spectator.describe "`all` matcher" do
+  context "array usage" do
+    describe [1, 3, 5] do
+      it { is_expected.to all(be_odd) }
+      it { is_expected.to all(be_an(Int32)) } # Changed to Int32 to satisfy compiler.
+      it { is_expected.to all(be < 10) }
+
+      # deliberate failures
+      # TODO: Add support for expected failures.
+      xit { is_expected.to all(be_even) }
+      xit { is_expected.to all(be_a(String)) }
+      xit { is_expected.to all(be > 2) }
+    end
+  end
+
+  context "compound matcher usage" do
+    # Changed `include` to `contain` to match our own.
+    # `include` is a keyword and can't be used as a method name in Crystal.
+
+    # TODO: Add support for compound matchers.
+    describe ["anything", "everything", "something"] do
+      xit { is_expected.to all(be_a(String)) }    # .and contain("thing") ) }
+      xit { is_expected.to all(be_a(String)) }    # .and end_with("g") ) }
+      xit { is_expected.to all(start_with("s")) } # .or contain("y") ) }
+
+      # deliberate failures
+      # TODO: Add support for expected failures.
+      # TODO: Add support for compound matchers.
+      xit { is_expected.to all(contain("foo")) }  # .and contain("bar") ) }
+      xit { is_expected.to all(be_a(String)) }    # .and start_with("a") ) }
+      xit { is_expected.to all(start_with("a")) } # .or contain("z") ) }
+    end
+  end
+end