diff --git a/Library/Homebrew/test/resource_spec.rb b/Library/Homebrew/test/resource_spec.rb
new file mode 100644
index 0000000000..6a04195389
--- /dev/null
+++ b/Library/Homebrew/test/resource_spec.rb
@@ -0,0 +1,147 @@
+require "resource"
+
+describe Resource do
+  subject { described_class.new("test") }
+
+  describe "#url" do
+    it "sets the URL" do
+      subject.url("foo")
+      expect(subject.url).to eq("foo")
+    end
+
+    it "can set the URL with specifications" do
+      subject.url("foo", branch: "master")
+      expect(subject.url).to eq("foo")
+      expect(subject.specs).to eq(branch: "master")
+    end
+
+    it "can set the URL with a custom download strategy class" do
+      strategy = Class.new(AbstractDownloadStrategy)
+      subject.url("foo", using: strategy)
+      expect(subject.url).to eq("foo")
+      expect(subject.download_strategy).to eq(strategy)
+    end
+
+    it "can set the URL with specifications and a custom download strategy class" do
+      strategy = Class.new(AbstractDownloadStrategy)
+      subject.url("foo", using: strategy, branch: "master")
+      expect(subject.url).to eq("foo")
+      expect(subject.specs).to eq(branch: "master")
+      expect(subject.download_strategy).to eq(strategy)
+    end
+
+    it "can set the URL with a custom download strategy symbol" do
+      subject.url("foo", using: :git)
+      expect(subject.url).to eq("foo")
+      expect(subject.download_strategy).to eq(GitDownloadStrategy)
+    end
+
+    it "raises an error if the download strategy class is unkown" do
+      expect { subject.url("foo", using: Class.new) }.to raise_error(TypeError)
+    end
+
+    it "does not mutate the specifications hash" do
+      specs = { using: :git, branch: "master" }
+      subject.url("foo", specs)
+      expect(subject.specs).to eq(branch: "master")
+      expect(subject.using).to eq(:git)
+      expect(specs).to eq(using: :git, branch: "master")
+    end
+  end
+
+  describe "#version" do
+    it "sets the version" do
+      subject.version("1.0")
+      expect(subject.version).to eq(Version.parse("1.0"))
+      expect(subject.version).not_to be_detected_from_url
+    end
+
+    it "can detect the version from a URL" do
+      subject.url("http://example.com/foo-1.0.tar.gz")
+      expect(subject.version).to eq(Version.parse("1.0"))
+      expect(subject.version).to be_detected_from_url
+    end
+
+    it "can set the version with a scheme" do
+      klass = Class.new(Version)
+      subject.version klass.new("1.0")
+      expect(subject.version).to eq(Version.parse("1.0"))
+      expect(subject.version).to be_a(klass)
+    end
+
+    it "can set the version from a tag" do
+      subject.url("http://example.com/foo-1.0.tar.gz", tag: "v1.0.2")
+      expect(subject.version).to eq(Version.parse("1.0.2"))
+      expect(subject.version).to be_detected_from_url
+    end
+
+    it "rejects non-string versions" do
+      expect { subject.version(1) }.to raise_error(TypeError)
+      expect { subject.version(2.0) }.to raise_error(TypeError)
+      expect { subject.version(Object.new) }.to raise_error(TypeError)
+    end
+
+    it "returns nil if unset" do
+      expect(subject.version).to be nil
+    end
+  end
+
+  describe "#mirrors" do
+    it "is empty by defaults" do
+      expect(subject.mirrors).to be_empty
+    end
+
+    it "returns an array of mirrors added with #mirror" do
+      subject.mirror("foo")
+      subject.mirror("bar")
+      expect(subject.mirrors).to eq(%w[foo bar])
+    end
+  end
+
+  describe "#checksum" do
+    it "returns nil if unset" do
+      expect(subject.checksum).to be nil
+    end
+
+    it "returns the checksum set with #sha256" do
+      subject.sha256(TEST_SHA256)
+      expect(subject.checksum).to eq(Checksum.new(:sha256, TEST_SHA256))
+    end
+  end
+
+  describe "#download_strategy" do
+    it "returns the download strategy" do
+      strategy = Object.new
+      expect(DownloadStrategyDetector)
+        .to receive(:detect).with("foo", nil).and_return(strategy)
+      subject.url("foo")
+      expect(subject.download_strategy).to eq(strategy)
+    end
+  end
+
+  specify "#verify_download_integrity_missing" do
+    fn = Pathname.new("test")
+
+    allow(fn).to receive(:file?).and_return(true)
+    expect(fn).to receive(:verify_checksum).and_raise(ChecksumMissingError)
+    expect(fn).to receive(:sha256)
+
+    shutup do
+      subject.verify_download_integrity(fn)
+    end
+  end
+
+  specify "#verify_download_integrity_mismatch" do
+    fn = double(file?: true)
+    checksum = subject.sha256(TEST_SHA256)
+
+    expect(fn).to receive(:verify_checksum).with(checksum)
+      .and_raise(ChecksumMismatchError.new(fn, checksum, Object.new))
+
+    shutup do
+      expect {
+        subject.verify_download_integrity(fn)
+      }.to raise_error(ChecksumMismatchError)
+    end
+  end
+end
diff --git a/Library/Homebrew/test/resource_test.rb b/Library/Homebrew/test/resource_test.rb
deleted file mode 100644
index d982a7c337..0000000000
--- a/Library/Homebrew/test/resource_test.rb
+++ /dev/null
@@ -1,133 +0,0 @@
-require "testing_env"
-require "resource"
-
-class ResourceTests < Homebrew::TestCase
-  def setup
-    super
-    @resource = Resource.new("test")
-  end
-
-  def test_url
-    @resource.url("foo")
-    assert_equal "foo", @resource.url
-  end
-
-  def test_url_with_specs
-    @resource.url("foo", branch: "master")
-    assert_equal "foo", @resource.url
-    assert_equal({ branch: "master" }, @resource.specs)
-  end
-
-  def test_url_with_custom_download_strategy_class
-    strategy = Class.new(AbstractDownloadStrategy)
-    @resource.url("foo", using: strategy)
-    assert_equal "foo", @resource.url
-    assert_equal strategy, @resource.download_strategy
-  end
-
-  def test_url_with_specs_and_download_strategy
-    strategy = Class.new(AbstractDownloadStrategy)
-    @resource.url("foo", using: strategy, branch: "master")
-    assert_equal "foo", @resource.url
-    assert_equal({ branch: "master" }, @resource.specs)
-    assert_equal strategy, @resource.download_strategy
-  end
-
-  def test_url_with_custom_download_strategy_symbol
-    @resource.url("foo", using: :git)
-    assert_equal "foo", @resource.url
-    assert_equal GitDownloadStrategy, @resource.download_strategy
-  end
-
-  def test_raises_for_unknown_download_strategy_class
-    assert_raises(TypeError) { @resource.url("foo", using: Class.new) }
-  end
-
-  def test_does_not_mutate_specs_hash
-    specs = { using: :git, branch: "master" }
-    @resource.url("foo", specs)
-    assert_equal({ branch: "master" }, @resource.specs)
-    assert_equal(:git, @resource.using)
-    assert_equal({ using: :git, branch: "master" }, specs)
-  end
-
-  def test_version
-    @resource.version("1.0")
-    assert_version_equal "1.0", @resource.version
-    refute_predicate @resource.version, :detected_from_url?
-  end
-
-  def test_version_from_url
-    @resource.url("http://example.com/foo-1.0.tar.gz")
-    assert_version_equal "1.0", @resource.version
-    assert_predicate @resource.version, :detected_from_url?
-  end
-
-  def test_version_with_scheme
-    klass = Class.new(Version)
-    @resource.version klass.new("1.0")
-    assert_version_equal "1.0", @resource.version
-    assert_instance_of klass, @resource.version
-  end
-
-  def test_version_from_tag
-    @resource.url("http://example.com/foo-1.0.tar.gz", tag: "v1.0.2")
-    assert_version_equal "1.0.2", @resource.version
-    assert_predicate @resource.version, :detected_from_url?
-  end
-
-  def test_rejects_non_string_versions
-    assert_raises(TypeError) { @resource.version(1) }
-    assert_raises(TypeError) { @resource.version(2.0) }
-    assert_raises(TypeError) { @resource.version(Object.new) }
-  end
-
-  def test_version_when_url_is_not_set
-    assert_nil @resource.version
-  end
-
-  def test_mirrors
-    assert_empty @resource.mirrors
-    @resource.mirror("foo")
-    @resource.mirror("bar")
-    assert_equal %w[foo bar], @resource.mirrors
-  end
-
-  def test_checksum_setters
-    assert_nil @resource.checksum
-    @resource.sha256(TEST_SHA256)
-    assert_equal Checksum.new(:sha256, TEST_SHA256), @resource.checksum
-  end
-
-  def test_download_strategy
-    strategy = Object.new
-    DownloadStrategyDetector
-      .expects(:detect).with("foo", nil).returns(strategy)
-    @resource.url("foo")
-    assert_equal strategy, @resource.download_strategy
-  end
-
-  def test_verify_download_integrity_missing
-    fn = Pathname.new("test")
-
-    fn.stubs(file?: true)
-    fn.expects(:verify_checksum).raises(ChecksumMissingError)
-    fn.expects(:sha256)
-
-    shutup { @resource.verify_download_integrity(fn) }
-  end
-
-  def test_verify_download_integrity_mismatch
-    fn = stub(file?: true)
-    checksum = @resource.sha256(TEST_SHA256)
-
-    fn.expects(:verify_checksum).with(checksum)
-      .raises(ChecksumMismatchError.new(fn, checksum, Object.new))
-
-    shutup do
-      assert_raises(ChecksumMismatchError) do
-        @resource.verify_download_integrity(fn)
-      end
-    end
-  end
-end