diff --git a/app/lib/tag_manager.rb b/app/lib/tag_manager.rb
index 55aed92e3ac..f1a2234dc44 100644
--- a/app/lib/tag_manager.rb
+++ b/app/lib/tag_manager.rb
@@ -93,8 +93,6 @@ class TagManager
       account_url(target)
     when :note, :comment, :activity
       unique_tag(target.created_at, target.id, 'Status')
-    else
-      unique_tag(target.stream_entry.created_at, target.stream_entry.activity_id, target.stream_entry.activity_type)
     end
   end
 
@@ -106,8 +104,6 @@ class TagManager
       short_account_url(target)
     when :note, :comment, :activity
       short_account_status_url(target.account, target)
-    else
-      account_stream_entry_url(target.account, target.stream_entry)
     end
   end
 end
diff --git a/spec/lib/tag_manager_spec.rb b/spec/lib/tag_manager_spec.rb
index cbb427a8c17..1fae6bec458 100644
--- a/spec/lib/tag_manager_spec.rb
+++ b/spec/lib/tag_manager_spec.rb
@@ -1,23 +1,152 @@
 require 'rails_helper'
 
 RSpec.describe TagManager do
-  let(:local_domain) { Rails.configuration.x.local_domain }
+  describe '#local_domain?' do
+    # The following comparisons MUST be case-insensitive.
+
+    around do |example|
+      original_local_domain = Rails.configuration.x.local_domain
+      Rails.configuration.x.local_domain = 'domain'
+
+      example.run
+
+      Rails.configuration.x.local_domain = original_local_domain
+    end
+
+    it 'returns true for nil' do
+      expect(TagManager.instance.local_domain?(nil)).to eq true
+    end
+
+    it 'returns true if the slash-stripped string equals to local domain' do
+      expect(TagManager.instance.local_domain?('DoMaIn/')).to eq true
+    end
+
+    it 'returns false for irrelevant string' do
+      expect(TagManager.instance.local_domain?('DoMaIn!')).to eq false
+    end
+  end
+
+  describe '#web_domain?' do
+    # The following comparisons MUST be case-insensitive.
+
+    around do |example|
+      original_web_domain = Rails.configuration.x.web_domain
+      Rails.configuration.x.web_domain = 'domain'
+
+      example.run
+
+      Rails.configuration.x.web_domain = original_web_domain
+    end
+
+    it 'returns true for nil' do
+      expect(TagManager.instance.web_domain?(nil)).to eq true
+    end
+
+    it 'returns true if the slash-stripped string equals to web domain' do
+      expect(TagManager.instance.web_domain?('DoMaIn/')).to eq true
+    end
+
+    it 'returns false for string with irrelevant characters' do
+      expect(TagManager.instance.web_domain?('DoMaIn!')).to eq false
+    end
+  end
+
+  describe '#normalize_domain' do
+    it 'returns nil if the given parameter is nil' do
+      expect(TagManager.instance.normalize_domain(nil)).to eq nil
+    end
+
+    it 'returns normalized domain' do
+      expect(TagManager.instance.normalize_domain('DoMaIn/')).to eq 'domain'
+    end
+  end
+
+  describe '#local_url?' do
+    around do |example|
+      original_local_domain = Rails.configuration.x.local_domain
+      example.run
+      Rails.configuration.x.local_domain = original_local_domain
+    end
+
+    it 'returns true if the normalized string with port is local URL' do
+      Rails.configuration.x.local_domain = 'domain:42'
+      expect(TagManager.instance.local_url?('https://DoMaIn:42/')).to eq true
+    end
+
+    it 'returns true if the normalized string without port is local URL' do
+      Rails.configuration.x.local_domain = 'domain'
+      expect(TagManager.instance.local_url?('https://DoMaIn/')).to eq true
+    end
+
+    it 'returns false for string with irrelevant characters' do
+      Rails.configuration.x.local_domain = 'domain'
+      expect(TagManager.instance.local_url?('https://domainn/')).to eq false
+    end
+  end
+
+  describe '#same_acct?' do
+    # The following comparisons MUST be case-insensitive.
+
+    it 'returns true if the needle has a correct username and domain for remote user' do
+      expect(TagManager.instance.same_acct?('username@domain', 'UsErNaMe@DoMaIn')).to eq true
+    end
+
+    it 'returns false if the needle is missing a domain for remote user' do
+      expect(TagManager.instance.same_acct?('username@domain', 'UsErNaMe')).to eq false
+    end
+
+    it 'returns false if the needle has an incorrect domain for remote user' do
+      expect(TagManager.instance.same_acct?('username@domain', 'UsErNaMe@incorrect')).to eq false
+    end
+
+    it 'returns false if the needle has an incorrect username for remote user' do
+      expect(TagManager.instance.same_acct?('username@domain', 'incorrect@DoMaIn')).to eq false
+    end
+
+    it 'returns true if the needle has a correct username and domain for local user' do
+      expect(TagManager.instance.same_acct?('username', 'UsErNaMe@Cb6E6126.nGrOk.Io')).to eq true
+    end
+
+    it 'returns true if the needle is missing a domain for local user' do
+      expect(TagManager.instance.same_acct?('username', 'UsErNaMe')).to eq true
+    end
+
+    it 'returns false if the needle has an incorrect username for local user' do
+      expect(TagManager.instance.same_acct?('username', 'UsErNaM@Cb6E6126.nGrOk.Io')).to eq false
+    end
+
+    it 'returns false if the needle has an incorrect domain for local user' do
+      expect(TagManager.instance.same_acct?('username', 'incorrect@Cb6E6126.nGrOk.Io')).to eq false
+    end
+  end
 
   describe '#unique_tag' do
-    it 'returns a string' do
-      expect(TagManager.instance.unique_tag(Time.now, 12, 'Status')).to be_a String
+    it 'returns a unique tag' do
+      expect(TagManager.instance.unique_tag(Time.utc(2000), 12, 'Status')).to eq 'tag:cb6e6126.ngrok.io,2000-01-01:objectId=12:objectType=Status'
     end
   end
 
   describe '#unique_tag_to_local_id' do
     it 'returns the ID part' do
-      expect(TagManager.instance.unique_tag_to_local_id("tag:#{local_domain};objectId=12:objectType=Status", 'Status')).to eql '12'
+      expect(TagManager.instance.unique_tag_to_local_id('tag:cb6e6126.ngrok.io,2000-01-01:objectId=12:objectType=Status', 'Status')).to eql '12'
+    end
+
+    it 'returns nil if it is not local id' do
+      expect(TagManager.instance.unique_tag_to_local_id('tag:remote,2000-01-01:objectId=12:objectType=Status', 'Status')).to eq nil
+    end
+
+    it 'returns nil if it is not expected type' do
+      expect(TagManager.instance.unique_tag_to_local_id('tag:cb6e6126.ngrok.io,2000-01-01:objectId=12:objectType=Block', 'Status')).to eq nil
+    end
+
+    it 'returns nil if it does not have object ID' do
+      expect(TagManager.instance.unique_tag_to_local_id('tag:cb6e6126.ngrok.io,2000-01-01:objectType=Status', 'Status')).to eq nil
     end
   end
 
   describe '#local_id?' do
     it 'returns true for a local ID' do
-      expect(TagManager.instance.local_id?("tag:#{local_domain};objectId=12:objectType=Status")).to be true
+      expect(TagManager.instance.local_id?('tag:cb6e6126.ngrok.io;objectId=12:objectType=Status')).to be true
     end
 
     it 'returns false for a foreign ID' do
@@ -26,49 +155,85 @@ RSpec.describe TagManager do
   end
 
   describe '#uri_for' do
-    let(:alice)  { Fabricate(:account, username: 'alice') }
-    let(:bob)    { Fabricate(:account, username: 'bob') }
-    let(:status) { Fabricate(:status, text: 'Hello world', account: alice) }
-
     subject { TagManager.instance.uri_for(target) }
 
-    context 'Account' do
-      let(:target) { alice }
+    context 'activity object' do
+      let(:target) { Fabricate(:status, reblog: Fabricate(:status)).stream_entry }
 
-      it 'returns a string' do
-        expect(subject).to be_a String
+      before { target.update!(created_at: '2000-01-01T00:00:00Z') }
+
+      it 'returns the unique tag for status' do
+        expect(target.object_type).to eq :activity
+        is_expected.to eq "tag:cb6e6126.ngrok.io,2000-01-01:objectId=#{target.id}:objectType=Status"
       end
     end
 
-    context 'Status' do
-      let(:target) { status }
+    context 'comment object' do
+      let(:target) { Fabricate(:status, created_at: '2000-01-01T00:00:00Z', reply: true) }
 
-      it 'returns a string' do
-        expect(subject).to be_a String
+      it 'returns the unique tag for status' do
+        expect(target.object_type).to eq :comment
+        is_expected.to eq "tag:cb6e6126.ngrok.io,2000-01-01:objectId=#{target.id}:objectType=Status"
+      end
+    end
+
+    context 'note object' do
+      let(:target) { Fabricate(:status, created_at: '2000-01-01T00:00:00Z', reply: false, thread: nil) }
+
+      it 'returns the unique tag for status' do
+        expect(target.object_type).to eq :note
+        is_expected.to eq "tag:cb6e6126.ngrok.io,2000-01-01:objectId=#{target.id}:objectType=Status"
+      end
+    end
+
+    context 'person object' do
+      let(:target) { Fabricate(:account, username: 'alice') }
+
+      it 'returns the URL for account' do
+        expect(target.object_type).to eq :person
+        is_expected.to eq 'https://cb6e6126.ngrok.io/users/alice'
       end
     end
   end
 
   describe '#url_for' do
-    let(:alice)  { Fabricate(:account, username: 'alice') }
-    let(:bob)    { Fabricate(:account, username: 'bob') }
-    let(:status) { Fabricate(:status, text: 'Hello world', account: alice) }
+    let(:alice) { Fabricate(:account, username: 'alice') }
 
     subject { TagManager.instance.url_for(target) }
 
-    context 'Account' do
-      let(:target) { alice }
+    context 'activity object' do
+      let(:target) { Fabricate(:status, account: alice, reblog: Fabricate(:status)).stream_entry }
 
-      it 'returns a URL' do
-        expect(subject).to be_a String
+      it 'returns the unique tag for status' do
+        expect(target.object_type).to eq :activity
+        is_expected.to eq "https://cb6e6126.ngrok.io/@alice/#{target.id}"
       end
     end
 
-    context 'Status' do
-      let(:target) { status }
+    context 'comment object' do
+      let(:target) { Fabricate(:status, account: alice, reply: true) }
 
-      it 'returns a URL' do
-        expect(subject).to be_a String
+      it 'returns the unique tag for status' do
+        expect(target.object_type).to eq :comment
+        is_expected.to eq "https://cb6e6126.ngrok.io/@alice/#{target.id}"
+      end
+    end
+
+    context 'note object' do
+      let(:target) { Fabricate(:status, account: alice, reply: false, thread: nil) }
+
+      it 'returns the unique tag for status' do
+        expect(target.object_type).to eq :note
+        is_expected.to eq "https://cb6e6126.ngrok.io/@alice/#{target.id}"
+      end
+    end
+
+    context 'person object' do
+      let(:target) { alice }
+
+      it 'returns the URL for account' do
+        expect(target.object_type).to eq :person
+        is_expected.to eq 'https://cb6e6126.ngrok.io/@alice'
       end
     end
   end