diff --git a/Library/Homebrew/test/x11_requirement_spec.rb b/Library/Homebrew/test/x11_requirement_spec.rb
new file mode 100644
index 0000000000..f60c8bffea
--- /dev/null
+++ b/Library/Homebrew/test/x11_requirement_spec.rb
@@ -0,0 +1,36 @@
+require "requirements/x11_requirement"
+
+describe X11Requirement do
+  let(:default_name) { "x11" }
+
+  describe "#name" do
+    it "defaults to x11" do
+      expect(subject.name).to eq(default_name)
+    end
+  end
+
+  describe "#eql?" do
+    it "returns true if the names are equal" do
+      other = described_class.new(default_name)
+      expect(subject).to eql(other)
+    end
+
+    it "and returns false if the names differ" do
+      other = described_class.new("foo")
+      expect(subject).not_to eql(other)
+    end
+
+    it "returns false if the minimum version differs" do
+      other = described_class.new(default_name, ["2.5"])
+      expect(subject).not_to eql(other)
+    end
+  end
+
+  describe "#modify_build_environment" do
+    it "calls ENV#x11" do
+      allow(subject).to receive(:satisfied?).and_return(true)
+      expect(ENV).to receive(:x11)
+      subject.modify_build_environment
+    end
+  end
+end
diff --git a/Library/Homebrew/test/x11_requirement_test.rb b/Library/Homebrew/test/x11_requirement_test.rb
deleted file mode 100644
index b82a59e53c..0000000000
--- a/Library/Homebrew/test/x11_requirement_test.rb
+++ /dev/null
@@ -1,31 +0,0 @@
-require "testing_env"
-require "requirements/x11_requirement"
-
-class X11RequirementTests < Homebrew::TestCase
-  def test_eql_instances_are_eql
-    x = X11Requirement.new
-    y = X11Requirement.new
-    assert_eql x, y
-    assert_equal x.hash, y.hash
-  end
-
-  def test_not_eql_when_hashes_differ
-    x = X11Requirement.new("foo")
-    y = X11Requirement.new
-    refute_eql x, y
-    refute_equal x.hash, y.hash
-  end
-
-  def test_different_min_version
-    x = X11Requirement.new
-    y = X11Requirement.new("x11", %w[2.5])
-    refute_eql x, y
-  end
-
-  def test_x_env
-    x = X11Requirement.new
-    x.stubs(:satisfied?).returns(true)
-    ENV.expects(:x11)
-    x.modify_build_environment
-  end
-end