diff --git a/spec/controllers/inbox_controller_spec.rb b/spec/controllers/inbox_controller_spec.rb
index b7426e7b..6cb2e128 100644
--- a/spec/controllers/inbox_controller_spec.rb
+++ b/spec/controllers/inbox_controller_spec.rb
@@ -6,21 +6,264 @@ describe InboxController, type: :controller do
   let(:user) { FactoryBot.create(:user) }
 
   describe "#show" do
+    shared_examples_for "sets the expected ivars" do
+      let(:expected_assigns) { {} }
+
+      it "sets the expected ivars" do
+        subject
+
+        expected_assigns.each do |name, value|
+          expect(assigns[name]).to eq(value)
+        end
+      end
+    end
+
     subject { get :show }
 
+    it "redirects to the login page when not signed in" do
+      expect(subject).to redirect_to(new_user_session_path)
+    end
+
     context "when user is signed in" do
       before(:each) { sign_in(user) }
 
-      it "shows the inbox" do
+      it "renders the correct template" do
         subject
         expect(response).to render_template("show")
       end
+
+      context "when inbox is empty" do
+        include_examples "sets the expected ivars",
+                         inbox:               [],
+                         inbox_last_id:       nil,
+                         more_data_available: false,
+                         inbox_count:         0,
+                         delete_id:           "ib-delete-all",
+                         disabled:            true
+      end
+
+      context "when inbox has an amount of questions less than page size" do
+        let!(:inbox_entry) { Inbox.create(user:, new: true, question: FactoryBot.create(:question)) }
+
+        include_examples "sets the expected ivars" do
+          let(:expected_assigns) do
+            {
+              inbox:               [inbox_entry],
+              inbox_last_id:       inbox_entry.id,
+              more_data_available: false,
+              inbox_count:         1,
+              delete_id:           "ib-delete-all",
+              disabled:            nil
+            }
+          end
+        end
+
+        context "when requested the turbo stream format" do
+          subject { get :show, format: :turbo_stream }
+
+          it "updates the inbox entry status" do
+            expect { subject }.to change { inbox_entry.reload.new? }.from(true).to(false)
+          end
+        end
+      end
+
+      context "when inbox has an amount of questions more than page size" do
+        let(:inbox_entry_fillers_page1) do
+          # 9 times => 1 entry less than default page size
+          9.times.map { Inbox.create(user:, question: FactoryBot.create(:question)) }
+        end
+        let(:last_inbox_entry_page1) { Inbox.create(user:, question: FactoryBot.create(:question)) }
+        let(:inbox_entry_fillers_page2) do
+          5.times.map { Inbox.create(user:, question: FactoryBot.create(:question)) }
+        end
+        let(:last_inbox_entry_page2) { Inbox.create(user:, question: FactoryBot.create(:question)) }
+
+        before do
+          # create inbox entries in reverse so pagination works as expected
+          last_inbox_entry_page2
+          inbox_entry_fillers_page2
+          last_inbox_entry_page1
+          inbox_entry_fillers_page1
+        end
+
+        include_examples "sets the expected ivars" do
+          let(:expected_assigns) do
+            {
+              inbox:               [*inbox_entry_fillers_page1.reverse, last_inbox_entry_page1],
+              inbox_last_id:       last_inbox_entry_page1.id,
+              more_data_available: true,
+              inbox_count:         16,
+              delete_id:           "ib-delete-all",
+              disabled:            nil
+            }
+          end
+        end
+
+        context "when passed the last_id param" do
+          subject { get :show, params: { last_id: last_inbox_entry_page1.id } }
+
+          include_examples "sets the expected ivars" do
+            let(:expected_assigns) do
+              {
+                inbox:               [*inbox_entry_fillers_page2.reverse, last_inbox_entry_page2],
+                inbox_last_id:       last_inbox_entry_page2.id,
+                more_data_available: false,
+                inbox_count:         16,
+                delete_id:           "ib-delete-all",
+                disabled:            nil
+              }
+            end
+          end
+        end
+      end
+
+      context "when passed the author param" do
+        let!(:other_user) { FactoryBot.create(:user) }
+        let!(:unrelated_user) { FactoryBot.create(:user) }
+
+        let!(:generic_inbox_entry1) do
+          Inbox.create(
+            user:,
+            question: FactoryBot.create(
+              :question,
+              user:                unrelated_user,
+              author_is_anonymous: false
+            )
+          )
+        end
+        let!(:generic_inbox_entry2) { Inbox.create(user:, question: FactoryBot.create(:question)) }
+
+        subject { get :show, params: { author: author_param } }
+
+        context "with a nonexisting screen name" do
+          let(:author_param) { "xXx420MegaGamer2003xXx" }
+
+          it "sets the error flash" do
+            subject
+            expect(flash[:error]).to eq "No user with the name @xXx420MegaGamer2003xXx found, showing entries from all users instead!"
+          end
+
+          include_examples "sets the expected ivars" do
+            let(:expected_assigns) do
+              {
+                inbox:               [generic_inbox_entry2, generic_inbox_entry1],
+                inbox_last_id:       generic_inbox_entry1.id,
+                more_data_available: false,
+                inbox_count:         2,
+                delete_id:           "ib-delete-all",
+                disabled:            nil
+              }
+            end
+          end
+        end
+
+        context "with an existing screen name" do
+          let(:author_param) { other_user.screen_name }
+
+          context "with no questions from the other user in the inbox" do
+            it { is_expected.to redirect_to inbox_path }
+
+            it "sets the info flash" do
+              subject
+              expect(flash[:info]).to eq "No questions from @#{other_user.screen_name} found, showing entries from all users instead!"
+            end
+
+            include_examples "sets the expected ivars" do
+              # these are the ivars set before the redirect happened
+              let(:expected_assigns) do
+                {
+                  inbox:               [],
+                  inbox_last_id:       nil,
+                  more_data_available: false,
+                  inbox_count:         0,
+                  delete_id:           "ib-delete-all",
+                  disabled:            true
+                }
+              end
+            end
+          end
+
+          context "with no non-anonymous questions from the other user in the inbox" do
+            let!(:anonymous_inbox_entry) do
+              Inbox.create(
+                user:,
+                question: FactoryBot.create(
+                  :question,
+                  user:                other_user,
+                  author_is_anonymous: true
+                )
+              )
+            end
+
+            it { is_expected.to redirect_to inbox_path }
+
+            it "sets the info flash" do
+              subject
+              expect(flash[:info]).to eq "No questions from @#{other_user.screen_name} found, showing entries from all users instead!"
+            end
+
+            include_examples "sets the expected ivars" do
+              # these are the ivars set before the redirect happened
+              let(:expected_assigns) do
+                {
+                  inbox:               [],
+                  inbox_last_id:       nil,
+                  more_data_available: false,
+                  inbox_count:         0,
+                  delete_id:           "ib-delete-all",
+                  disabled:            true
+                }
+              end
+            end
+          end
+
+          context "with both non-anonymous and anonymous questions from the other user in the inbox" do
+            let!(:non_anonymous_inbox_entry) do
+              Inbox.create(
+                user:,
+                question: FactoryBot.create(
+                  :question,
+                  user:                other_user,
+                  author_is_anonymous: false
+                )
+              )
+            end
+            let!(:anonymous_inbox_entry) do
+              Inbox.create(
+                user:,
+                question: FactoryBot.create(
+                  :question,
+                  user:                other_user,
+                  author_is_anonymous: true
+                )
+              )
+            end
+
+            include_examples "sets the expected ivars" do
+              let(:expected_assigns) do
+                {
+                  inbox:               [non_anonymous_inbox_entry],
+                  inbox_last_id:       non_anonymous_inbox_entry.id,
+                  more_data_available: false,
+                  inbox_count:         1,
+                  delete_id:           "ib-delete-all-author",
+                  disabled:            nil
+                }
+              end
+            end
+          end
+        end
+      end
     end
   end
 
   describe "#create" do
     subject { post :create }
 
+    it "redirects to the login page when not signed in" do
+      expect(subject).to redirect_to(new_user_session_path)
+    end
+
     context "when user is signed in" do
       before(:each) { sign_in(user) }