Add tests for equality matcher

spec/rspec/expectations/equality_matchers_spec.cr

@@ -0,0 +1,64 @@
+require "../../spec_helper"
+
+# Examples taken from:
+# https://relishapp.com/rspec/rspec-expectations/v/3-8/docs/built-in-matchers/equality-matchers
+# and modified to fit Spectator and Crystal.
+Spectator.describe "Equality matchers" do
+  context "compare using eq (==)" do
+    describe "a string" do
+      it "is equal to another string of the same value" do
+        expect("this string").to eq("this string")
+      end
+
+      it "is not equal to another string of a different value" do
+        expect("this string").not_to eq("a different string")
+      end
+    end
+
+    describe "an integer" do
+      it "is equal to a float for the same value" do
+        expect(5).to eq(5.0)
+      end
+    end
+  end
+
+  context "compare using ==" do
+    describe "a string" do
+      it "is equal to another string of the same value" do
+        expect("this string").to be == "this string"
+      end
+
+      it "is not equal to another string of a different value" do
+        expect("this string").not_to be == "a different string"
+      end
+    end
+
+    describe "an integer" do
+      it "is equal to a float of the same value" do
+        expect(5).to be == 5.0
+      end
+    end
+  end
+
+  # There are no #eql? and #equal? methods in Crystal, so these tests are skipped.
+
+  context "compare using be (same?)" do
+    it "is equal to itself" do
+      string = "this string"
+      expect(string).to be(string)
+    end
+
+    it "is not equal to another reference of the same value" do
+      # Strings with identical contents are the same reference in Crystal.
+      # This test is modified to reflect that.
+      # expect("this string").not_to be("this string")
+      box1 = Box.new("this string")
+      box2 = Box.new("this string")
+      expect(box1).not_to be(box2)
+    end
+
+    it "is not equal to another string of a different value" do
+      expect("this string").not_to be("a different string")
+    end
+  end
+end