added some tests

Gemfile

···
 gem "rake", "~> 13.0"
 gem "rspec", "~> 3.0"
 gem 'irb'
+gem 'mocha'
+gem 'webmock'

spec/dids/dholms.json

···
+{
+  "@context": [
+    "https://www.w3.org/ns/did/v1",
+    "https://w3id.org/security/multikey/v1",
+    "https://w3id.org/security/suites/secp256k1-2019/v1"
+  ],
+  "id": "did:plc:yk4dd2qkboz2yv6tpubpc6co",
+  "alsoKnownAs": [
+    "at://dholms.xyz"
+  ],
+  "verificationMethod": [
+    {
+      "id": "did:plc:yk4dd2qkboz2yv6tpubpc6co#atproto",
+      "type": "Multikey",
+      "controller": "did:plc:yk4dd2qkboz2yv6tpubpc6co",
+      "publicKeyMultibase": "zQ3shsJcHdhfpKyF3U6rBQziDHsY1ikwCAsqGWhdC1tgaPQxq"
+    }
+  ],
+  "service": [
+    {
+      "id": "#atproto_pds",
+      "type": "AtprotoPersonalDataServer",
+      "serviceEndpoint": "https://pds.dholms.xyz"
+    }
+  ]
+}

spec/dids/witchcraft.json

···
+{
+  "@context": [
+    "https://www.w3.org/ns/did/v1",
+    "https://w3id.org/security/multikey/v1",
+    "https://w3id.org/security/suites/secp256k1-2019/v1"
+  ],
+  "id": "did:web:witchcraft.systems",
+  "alsoKnownAs": [
+    "at://witchcraft.systems"
+  ],
+  "verificationMethod": [
+    {
+      "id": "did:web:witchcraft.systems#atproto",
+      "type": "Multikey",
+      "controller": "did:web:witchcraft.systems",
+      "publicKeyMultibase": "zQ3shqRWPzo6kSi1PDn1VXTVeaRiigsK3bxKLQ1gQ6UHqnVxW"
+    }
+  ],
+  "service": [
+    {
+      "id": "#atproto_pds",
+      "type": "AtprotoPersonalDataServer",
+      "serviceEndpoint": "https://pds.witchcraft.systems"
+    }
+  ]
+}

spec/resolver_spec.rb

···
+describe DIDKit::Resolver do
+  let(:sample_did) { 'did:plc:qhfo22pezo44fa3243z2h4ny' }
+
+  describe '#resolve_handle' do
+    context 'when handle resolves via HTTP' do
+      before do
+        Resolv::DNS.stubs(:open).returns([])
+      end
+
+      let(:handle) { 'barackobama.bsky.social' }
+
+      it 'should return a matching DID' do
+        stub_request(:get, "https://#{handle}/.well-known/atproto-did")
+          .to_return(body: sample_did)
+
+        result = subject.resolve_handle(handle)
+
+        result.should_not be_nil
+        result.should be_a(DID)
+        result.to_s.should == sample_did
+        result.resolved_by.should == :http
+      end
+
+      it 'should check DNS first' do
+        Resolv::DNS.expects(:open).returns([])
+        stub_request(:get, "https://#{handle}/.well-known/atproto-did")
+          .to_return(body: sample_did)
+
+        result = subject.resolve_handle(handle)
+      end
+
+      context 'when HTTP returns invalid text' do
+        it 'should return nil' do
+          stub_request(:get, "https://#{handle}/.well-known/atproto-did")
+            .to_return(body: "Welcome to nginx!")
+
+          result = subject.resolve_handle(handle)
+          result.should be_nil
+        end
+      end
+
+      context 'when HTTP returns bad response' do
+        it 'should return nil' do
+          stub_request(:get, "https://#{handle}/.well-known/atproto-did")
+            .to_return(status: 400, body: sample_did)
+
+          result = subject.resolve_handle(handle)
+          result.should be_nil
+        end
+      end
+
+      context 'when HTTP throws an exception' do
+        it 'should catch it and return nil' do
+          stub_request(:get, "https://#{handle}/.well-known/atproto-did")
+            .to_raise(Errno::ETIMEDOUT)
+
+          result = 0
+
+          expect {
+            result = subject.resolve_handle(handle)
+          }.to_not raise_error
+
+          result.should be_nil
+        end
+      end
+
+      context 'when HTTP response has a trailing newline' do
+        it 'should accept it' do
+          stub_request(:get, "https://#{handle}/.well-known/atproto-did")
+            .to_return(body: sample_did + "\n")
+
+          result = subject.resolve_handle(handle)
+
+          result.should_not be_nil
+          result.should be_a(DID)
+          result.to_s.should == sample_did
+        end
+      end
+    end
+
+    context 'when handle has a leading @' do
+      let(:handle) { '@pfrazee.com' }
+
+      before do
+        Resolv::DNS.stubs(:open).returns([])
+      end
+
+      it 'should also return a matching DID' do
+        stub_request(:get, "https://pfrazee.com/.well-known/atproto-did")
+          .to_return(body: sample_did)
+
+        result = subject.resolve_handle(handle)
+
+        result.should_not be_nil
+        result.should be_a(DID)
+        result.to_s.should == sample_did
+        result.resolved_by.should == :http
+      end
+    end
+
+    context 'when handle has a reserved TLD' do
+      let(:handle) { 'example.test' }
+
+      it 'should return nil' do
+        subject.resolve_handle(handle).should be_nil
+      end
+    end
+
+    context 'when a DID string is passed' do
+      let(:handle) { BSKY_APP_DID }
+
+      it 'should return that DID' do
+        result = subject.resolve_handle(handle)
+
+        result.should be_a(DID)
+        result.to_s.should == BSKY_APP_DID
+      end
+    end
+
+    context 'when a DID object is passed' do
+      let(:handle) { DID.new(BSKY_APP_DID) }
+
+      it 'should return a new DID object with that DID' do
+        result = subject.resolve_handle(handle)
+
+        result.should be_a(DID)
+        result.to_s.should == BSKY_APP_DID
+        result.equal?(handle).should == false
+      end
+    end
+  end
+
+  describe '#resolve_did' do
+    context 'when passed a did:plc string' do
+      let(:did) { 'did:plc:yk4dd2qkboz2yv6tpubpc6co' }
+
+      it 'should return a parsed DID document object' do
+        stub_request(:get, "https://plc.directory/#{did}")
+          .to_return(body: load_did_file('dholms.json'), headers: { 'Content-Type': 'application/did+ld+json; charset=utf-8' })
+
+        result = subject.resolve_did(did)
+        result.should be_a(DIDKit::Document)
+        result.handles.should == ['dholms.xyz']
+        result.pds_endpoint.should == 'https://pds.dholms.xyz'
+      end
+
+      it 'should require a valid content type' do
+        stub_request(:get, "https://plc.directory/#{did}")
+          .to_return(body: load_did_file('dholms.json'), headers: { 'Content-Type': 'text/plain' })
+
+        expect { subject.resolve_did(did) }.to raise_error(DIDKit::APIError)
+      end
+    end
+
+    context 'when passed a did:web string' do
+      let(:did) { 'did:web:witchcraft.systems' }
+
+      it 'should return a parsed DID document object' do
+        stub_request(:get, "https://witchcraft.systems/.well-known/did.json")
+          .to_return(body: load_did_file('witchcraft.json'), headers: { 'Content-Type': 'application/did+ld+json; charset=utf-8' })
+
+        result = subject.resolve_did(did)
+        result.should be_a(DIDKit::Document)
+        result.handles.should == ['witchcraft.systems']
+        result.pds_endpoint.should == 'https://pds.witchcraft.systems'
+      end
+
+      it 'should NOT require a valid content type' do
+        stub_request(:get, "https://witchcraft.systems/.well-known/did.json")
+          .to_return(body: load_did_file('witchcraft.json'), headers: { 'Content-Type': 'text/plain' })
+
+        result = subject.resolve_did(did)
+        result.should be_a(DIDKit::Document)
+        result.handles.should == ['witchcraft.systems']
+        result.pds_endpoint.should == 'https://pds.witchcraft.systems'
+      end
+    end
+  end
+end

spec/spec_helper.rb

···
 # frozen_string_literal: true
 
-require "didkit"
+require 'didkit'
+require 'webmock/rspec'
 
 RSpec.configure do |config|
   # Enable flags like --only-failures and --next-failure
   config.example_status_persistence_file_path = ".rspec_status"
 
-  # Disable RSpec exposing methods globally on `Module` and `main`
-  config.disable_monkey_patching!
-
   config.expect_with :rspec do |c|
-    c.syntax = :expect
+    c.syntax = [:should, :expect]
   end
+
+  config.mock_with :mocha
+end
+
+BSKY_APP_DID = 'did:plc:z72i7hdynmk6r22z27h6tvur'
+
+WebMock.enable!
+
+def load_did_file(name)
+  File.read(File.join(__dir__, 'dids', name))
 end