diff --git a/test/natalie/openssl_digest/append_test.rb b/test/natalie/openssl_digest/append_test.rb
new file mode 100644
index 0000000000..5cffee1286
--- /dev/null
+++ b/test/natalie/openssl_digest/append_test.rb
@@ -0,0 +1,6 @@
+require_relative '../../../spec/spec_helper'
+require_relative 'shared/update'
+
+describe "OpenSSL::Digest#<<" do
+  it_behaves_like :openssl_digest_update, :<<
+end
diff --git a/test/natalie/openssl_digest/block_length_test.rb b/test/natalie/openssl_digest/block_length_test.rb
new file mode 100644
index 0000000000..b868842040
--- /dev/null
+++ b/test/natalie/openssl_digest/block_length_test.rb
@@ -0,0 +1,44 @@
+require_relative '../../../spec/spec_helper'
+require_relative '../../../spec/library/digest/sha1/shared/constants'
+require_relative '../../../spec/library/digest/sha256/shared/constants'
+require_relative '../../../spec/library/digest/sha384/shared/constants'
+require_relative '../../../spec/library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#block_length" do
+  describe "block_length of OpenSSL::Digest.new(name)" do
+    it "returns a SHA1 block length" do
+      OpenSSL::Digest.new('sha1').block_length.should == SHA1Constants::BlockLength
+    end
+
+    it "returns a SHA256 block length" do
+      OpenSSL::Digest.new('sha256').block_length.should == SHA256Constants::BlockLength
+    end
+
+    it "returns a SHA384 block_length" do
+      OpenSSL::Digest.new('sha384').block_length.should == SHA384Constants::BlockLength
+    end
+
+    it "returns a SHA512 block_length" do
+      OpenSSL::Digest.new('sha512').block_length.should == SHA512Constants::BlockLength
+    end
+  end
+
+  describe "block_length of subclasses" do
+    it "returns a SHA1 block length" do
+      OpenSSL::Digest::SHA1.new.block_length.should == SHA1Constants::BlockLength
+    end
+
+    it "returns a SHA256 block length" do
+      OpenSSL::Digest::SHA256.new.block_length.should == SHA256Constants::BlockLength
+    end
+
+    it "returns a SHA384 block_length" do
+      OpenSSL::Digest::SHA384.new.block_length.should == SHA384Constants::BlockLength
+    end
+
+    it "returns a SHA512 block_length" do
+      OpenSSL::Digest::SHA512.new.block_length.should == SHA512Constants::BlockLength
+    end
+  end
+end
diff --git a/test/natalie/openssl_digest/digest_length_test.rb b/test/natalie/openssl_digest/digest_length_test.rb
new file mode 100644
index 0000000000..a18af5dbdf
--- /dev/null
+++ b/test/natalie/openssl_digest/digest_length_test.rb
@@ -0,0 +1,44 @@
+require_relative '../../../spec/spec_helper'
+require_relative '../../../spec/library/digest/sha1/shared/constants'
+require_relative '../../../spec/library/digest/sha256/shared/constants'
+require_relative '../../../spec/library/digest/sha384/shared/constants'
+require_relative '../../../spec/library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#digest_length" do
+  describe "digest_length of OpenSSL::Digest.new(name)" do
+    it "returns a SHA1 block length" do
+      OpenSSL::Digest.new('sha1').digest_length.should == SHA1Constants::DigestLength
+    end
+
+    it "returns a SHA256 block length" do
+      OpenSSL::Digest.new('sha256').digest_length.should == SHA256Constants::DigestLength
+    end
+
+    it "returns a SHA384 digest_length" do
+      OpenSSL::Digest.new('sha384').digest_length.should == SHA384Constants::DigestLength
+    end
+
+    it "returns a SHA512 digest_length" do
+      OpenSSL::Digest.new('sha512').digest_length.should == SHA512Constants::DigestLength
+    end
+  end
+
+  describe "digest_length of subclasses" do
+    it "returns a SHA1 block length" do
+      OpenSSL::Digest::SHA1.new.digest_length.should == SHA1Constants::DigestLength
+    end
+
+    it "returns a SHA256 block length" do
+      OpenSSL::Digest::SHA256.new.digest_length.should == SHA256Constants::DigestLength
+    end
+
+    it "returns a SHA384 digest_length" do
+      OpenSSL::Digest::SHA384.new.digest_length.should == SHA384Constants::DigestLength
+    end
+
+    it "returns a SHA512 digest_length" do
+      OpenSSL::Digest::SHA512.new.digest_length.should == SHA512Constants::DigestLength
+    end
+  end
+end
diff --git a/test/natalie/openssl_digest/digest_test.rb b/test/natalie/openssl_digest/digest_test.rb
new file mode 100644
index 0000000000..a4d823003f
--- /dev/null
+++ b/test/natalie/openssl_digest/digest_test.rb
@@ -0,0 +1,62 @@
+require_relative '../../../spec/spec_helper'
+require_relative '../../../spec/library/digest/sha1/shared/constants'
+require_relative '../../../spec/library/digest/sha256/shared/constants'
+require_relative '../../../spec/library/digest/sha384/shared/constants'
+require_relative '../../../spec/library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest class methods" do
+  describe ".digest" do
+    it "returns a SHA1 digest" do
+      OpenSSL::Digest.digest('sha1', SHA1Constants::Contents).should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      OpenSSL::Digest.digest('sha256', SHA256Constants::Contents).should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      OpenSSL::Digest.digest('sha384', SHA384Constants::Contents).should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      OpenSSL::Digest.digest('sha512', SHA512Constants::Contents).should == SHA512Constants::Digest
+    end
+  end
+
+  describe ".hexdigest" do
+    it "returns a SHA1 hexdigest" do
+      OpenSSL::Digest.hexdigest('sha1', SHA1Constants::Contents).should == SHA1Constants::Hexdigest
+    end
+
+    it "returns a SHA256 hexdigest" do
+      OpenSSL::Digest.hexdigest('sha256', SHA256Constants::Contents).should == SHA256Constants::Hexdigest
+    end
+
+    it "returns a SHA384 hexdigest" do
+      OpenSSL::Digest.hexdigest('sha384', SHA384Constants::Contents).should == SHA384Constants::Hexdigest
+    end
+
+    it "returns a SHA512 hexdigest" do
+      OpenSSL::Digest.hexdigest('sha512', SHA512Constants::Contents).should == SHA512Constants::Hexdigest
+    end
+  end
+
+  describe ".base64digest" do
+    it "returns a SHA1 base64digest" do
+      OpenSSL::Digest.base64digest('sha1', SHA1Constants::Contents).should == SHA1Constants::Base64digest
+    end
+
+    it "returns a SHA256 base64digest" do
+      OpenSSL::Digest.base64digest('sha256', SHA256Constants::Contents).should == SHA256Constants::Base64digest
+    end
+
+    it "returns a SHA384 base64digest" do
+      OpenSSL::Digest.base64digest('sha384', SHA384Constants::Contents).should == SHA384Constants::Base64digest
+    end
+
+    it "returns a SHA512 base64digest" do
+      OpenSSL::Digest.base64digest('sha512', SHA512Constants::Contents).should == SHA512Constants::Base64digest
+    end
+  end
+end
diff --git a/test/natalie/openssl_digest/initialize_test.rb b/test/natalie/openssl_digest/initialize_test.rb
new file mode 100644
index 0000000000..7631584c46
--- /dev/null
+++ b/test/natalie/openssl_digest/initialize_test.rb
@@ -0,0 +1,141 @@
+require_relative '../../../spec/spec_helper'
+require_relative '../../../spec/library/digest/sha1/shared/constants'
+require_relative '../../../spec/library/digest/sha256/shared/constants'
+require_relative '../../../spec/library/digest/sha384/shared/constants'
+require_relative '../../../spec/library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest initialization" do
+  describe "can be called with a digest name" do
+    it "returns a SHA1 object" do
+      OpenSSL::Digest.new("sha1").name.should == "SHA1"
+    end
+
+    it "returns a SHA256 object" do
+      OpenSSL::Digest.new("sha256").name.should == "SHA256"
+    end
+
+    it "returns a SHA384 object" do
+      OpenSSL::Digest.new("sha384").name.should == "SHA384"
+    end
+
+    it "returns a SHA512 object" do
+      OpenSSL::Digest.new("sha512").name.should ==  "SHA512"
+    end
+
+    it "throws an error when called with an unknown digest" do
+      -> { OpenSSL::Digest.new("wd40") }.should raise_error(RuntimeError, /Unsupported digest algorithm \(wd40\)/)
+    end
+
+    it "cannot be called with a symbol" do
+      -> { OpenSSL::Digest.new(:SHA1) }.should raise_error(TypeError, /wrong argument type Symbol/)
+    end
+
+    it "doest not call #to_str on the argument" do
+      name = mock("digest name")
+      name.should_not_receive(:to_str)
+      -> { OpenSSL::Digest.new(name) }.should raise_error(TypeError, /wrong argument type/)
+    end
+  end
+
+  describe "can be called with a digest object" do
+    it "returns a SHA1 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA1.new).name.should == "SHA1"
+    end
+
+    it "returns a SHA256 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA256.new).name.should == "SHA256"
+    end
+
+    it "returns a SHA384 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA384.new).name.should == "SHA384"
+    end
+
+    it "returns a SHA512 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA512.new).name.should ==  "SHA512"
+    end
+
+    it "cannot be called with a digest class" do
+      -> { OpenSSL::Digest.new(OpenSSL::Digest::SHA1) }.should raise_error(TypeError, /wrong argument type Class/)
+    end
+
+    it "ignores the state of the name object" do
+      sha1 = OpenSSL::Digest.new('sha1', SHA1Constants::Contents)
+      OpenSSL::Digest.new(sha1).digest.should == SHA1Constants::BlankDigest
+    end
+  end
+
+  describe "ititialization with an empty string" do
+    it "returns a SHA1 digest" do
+      OpenSSL::Digest.new("sha1").digest.should == SHA1Constants::BlankDigest
+    end
+
+    it "returns a SHA256 digest" do
+      OpenSSL::Digest.new("sha256").digest.should == SHA256Constants::BlankDigest
+    end
+
+    it "returns a SHA384 digest" do
+      OpenSSL::Digest.new("sha384").digest.should == SHA384Constants::BlankDigest
+    end
+
+    it "returns a SHA512 digest" do
+      OpenSSL::Digest.new("sha512").digest.should == SHA512Constants::BlankDigest
+    end
+  end
+
+  describe "can be called with a digest name and data" do
+    it "returns a SHA1 digest" do
+      OpenSSL::Digest.new("sha1", SHA1Constants::Contents).digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      OpenSSL::Digest.new("sha256", SHA256Constants::Contents).digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      OpenSSL::Digest.new("sha384", SHA384Constants::Contents).digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      OpenSSL::Digest.new("sha512", SHA512Constants::Contents).digest.should == SHA512Constants::Digest
+    end
+  end
+
+  context "can be called on subclasses" do
+    describe "can be called without data on subclasses" do
+      it "returns a SHA1 digest" do
+        OpenSSL::Digest::SHA1.new.digest.should == SHA1Constants::BlankDigest
+      end
+
+      it "returns a SHA256 digest" do
+        OpenSSL::Digest::SHA256.new.digest.should == SHA256Constants::BlankDigest
+      end
+
+      it "returns a SHA384 digest" do
+        OpenSSL::Digest::SHA384.new.digest.should == SHA384Constants::BlankDigest
+      end
+
+      it "returns a SHA512 digest" do
+        OpenSSL::Digest::SHA512.new.digest.should == SHA512Constants::BlankDigest
+      end
+    end
+
+    describe "can be called with data on subclasses" do
+      it "returns a SHA1 digest" do
+        OpenSSL::Digest::SHA1.new(SHA1Constants::Contents).digest.should == SHA1Constants::Digest
+      end
+
+      it "returns a SHA256 digest" do
+        OpenSSL::Digest::SHA256.new(SHA256Constants::Contents).digest.should == SHA256Constants::Digest
+      end
+
+      it "returns a SHA384 digest" do
+        OpenSSL::Digest::SHA384.new(SHA384Constants::Contents).digest.should == SHA384Constants::Digest
+      end
+
+      it "returns a SHA512 digest" do
+        OpenSSL::Digest::SHA512.new(SHA512Constants::Contents).digest.should == SHA512Constants::Digest
+      end
+    end
+  end
+end
diff --git a/test/natalie/openssl_digest/name_test.rb b/test/natalie/openssl_digest/name_test.rb
new file mode 100644
index 0000000000..964ee2dbdf
--- /dev/null
+++ b/test/natalie/openssl_digest/name_test.rb
@@ -0,0 +1,16 @@
+require_relative '../../../spec/spec_helper'
+require 'openssl'
+
+describe "OpenSSL::Digest#name" do
+  it "returns the name of digest when called on an instance" do
+    OpenSSL::Digest.new('SHA1').name.should == 'SHA1'
+  end
+
+  it "converts the name to the internal representation of OpenSSL" do
+    OpenSSL::Digest.new('sha1').name.should == 'SHA1'
+  end
+
+  it "works on subclasses too" do
+    OpenSSL::Digest::SHA1.new.name.should == 'SHA1'
+  end
+end
diff --git a/test/natalie/openssl_digest/reset_test.rb b/test/natalie/openssl_digest/reset_test.rb
new file mode 100644
index 0000000000..e08c1303d0
--- /dev/null
+++ b/test/natalie/openssl_digest/reset_test.rb
@@ -0,0 +1,38 @@
+require_relative '../../../spec/spec_helper'
+require_relative '../../../spec/library/digest/sha1/shared/constants'
+require_relative '../../../spec/library/digest/sha256/shared/constants'
+require_relative '../../../spec/library/digest/sha384/shared/constants'
+require_relative '../../../spec/library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#reset" do
+  describe "resets the state of the digest" do
+    it "works for a SHA1 digest" do
+      digest = OpenSSL::Digest.new('sha1', SHA1Constants::Contents)
+      digest.reset
+      digest.update(SHA1Constants::Contents)
+      digest.digest.should == SHA1Constants::Digest
+    end
+
+    it "works for a SHA256 digest" do
+      digest = OpenSSL::Digest.new('sha256', SHA256Constants::Contents)
+      digest.reset
+      digest.update(SHA256Constants::Contents)
+      digest.digest.should == SHA256Constants::Digest
+    end
+
+    it "works for a SHA384 digest" do
+      digest = OpenSSL::Digest.new('sha384', SHA384Constants::Contents)
+      digest.reset
+      digest.update(SHA384Constants::Contents)
+      digest.digest.should == SHA384Constants::Digest
+    end
+
+    it "works for a SHA512 digest" do
+      digest = OpenSSL::Digest.new('sha512', SHA512Constants::Contents)
+      digest.reset
+      digest.update(SHA512Constants::Contents)
+      digest.digest.should == SHA512Constants::Digest
+    end
+  end
+end
diff --git a/test/natalie/openssl_digest/shared/update.rb b/test/natalie/openssl_digest/shared/update.rb
new file mode 100644
index 0000000000..f69ef8aeec
--- /dev/null
+++ b/test/natalie/openssl_digest/shared/update.rb
@@ -0,0 +1,59 @@
+require_relative '../../../../spec/library/digest/sha1/shared/constants'
+require_relative '../../../../spec/library/digest/sha256/shared/constants'
+require_relative '../../../../spec/library/digest/sha384/shared/constants'
+require_relative '../../../../spec/library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe :openssl_digest_update, shared: true do
+  context "it supports full data chunks" do
+    it "returns a SHA1 digest" do
+      digest = OpenSSL::Digest.new('sha1')
+      digest.send(@method, SHA1Constants::Contents)
+      digest.digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      digest = OpenSSL::Digest.new('sha256')
+      digest.send(@method, SHA256Constants::Contents)
+      digest.digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      digest = OpenSSL::Digest.new('sha384')
+      digest.send(@method, SHA384Constants::Contents)
+      digest.digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      digest = OpenSSL::Digest.new('sha512')
+      digest.send(@method, SHA512Constants::Contents)
+      digest.digest.should == SHA512Constants::Digest
+    end
+  end
+
+  context "it support smaller chunks" do
+    it "returns a SHA1 digest" do
+      digest = OpenSSL::Digest.new('sha1')
+      SHA1Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      digest = OpenSSL::Digest.new('sha256')
+      SHA256Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      digest = OpenSSL::Digest.new('sha384')
+      SHA384Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      digest = OpenSSL::Digest.new('sha512')
+      SHA512Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA512Constants::Digest
+    end
+  end
+end
diff --git a/test/natalie/openssl_digest/update_test.rb b/test/natalie/openssl_digest/update_test.rb
new file mode 100644
index 0000000000..98bdf3b97e
--- /dev/null
+++ b/test/natalie/openssl_digest/update_test.rb
@@ -0,0 +1,6 @@
+require_relative '../../../spec/spec_helper'
+require_relative 'shared/update'
+
+describe "OpenSSL::Digest#update" do
+  it_behaves_like :openssl_digest_update, :update
+end