diff --git a/spec/fabricators/account_fabricator.rb b/spec/fabricators/account_fabricator.rb
index 534b8ae843..6ec89a1cb6 100644
--- a/spec/fabricators/account_fabricator.rb
+++ b/spec/fabricators/account_fabricator.rb
@@ -15,4 +15,5 @@ Fabricator(:account) do
   user                { |attrs| attrs[:domain].nil? ? Fabricate.build(:user, account: nil) : nil }
   uri                 { |attrs| attrs[:domain].nil? ? '' : "https://#{attrs[:domain]}/users/#{attrs[:username]}" }
   discoverable        true
+  indexable           true
 end
diff --git a/spec/models/fasp/backfill_request_spec.rb b/spec/models/fasp/backfill_request_spec.rb
index 397a9e942b..56ea70d5a7 100644
--- a/spec/models/fasp/backfill_request_spec.rb
+++ b/spec/models/fasp/backfill_request_spec.rb
@@ -3,5 +3,92 @@
 require 'rails_helper'
 
 RSpec.describe Fasp::BackfillRequest do
-  pending "add some examples to (or delete) #{__FILE__}"
+  describe '#next_objects' do
+    let(:account) { Fabricate(:account) }
+
+    before { Fabricate.times(3, :status, account:).sort_by(&:id) }
+
+    context 'with a new backfill request' do
+      subject { Fabricate(:fasp_backfill_request, max_count: 2) }
+
+      it 'returns the newest two statuses' do
+        expect(subject.next_objects).to eq [statuses[2], statuses[1]]
+      end
+    end
+
+    context 'with cursor set to second newest status' do
+      subject do
+        Fabricate(:fasp_backfill_request, max_count: 2, cursor: statuses[1].id)
+      end
+
+      it 'returns the oldest status' do
+        expect(subject.next_objects).to eq [statuses[0]]
+      end
+    end
+
+    context 'when all statuses are not `indexable`' do
+      subject { Fabricate(:fasp_backfill_request) }
+
+      let(:account) { Fabricate(:account, indexable: false) }
+
+      it 'returns no statuses' do
+        expect(subject.next_objects).to be_empty
+      end
+    end
+  end
+
+  describe '#next_uris' do
+    subject { Fabricate(:fasp_backfill_request) }
+
+    let(:statuses) { Fabricate.times(2, :status) }
+
+    it 'returns uris of the next objects' do
+      uris = statuses.map(&:uri)
+
+      expect(subject.next_uris).to match_array(uris)
+    end
+  end
+
+  describe '#more_objects_available?' do
+    subject { Fabricate(:fasp_backfill_request, max_count: 2) }
+
+    context 'when more objects are available' do
+      before { Fabricate.times(3, :status) }
+
+      it 'returns `true`' do
+        expect(subject.more_objects_available?).to be true
+      end
+    end
+
+    context 'when no more objects are available' do
+      before { Fabricate.times(2, :status) }
+
+      it 'returns `false`' do
+        expect(subject.more_objects_available?).to be false
+      end
+    end
+  end
+
+  describe '#advance!' do
+    subject { Fabricate(:fasp_backfill_request, max_count: 2) }
+
+    context 'when more objects are available' do
+      before { Fabricate.times(3, :status) }
+
+      it 'updates `cursor`' do
+        expect { subject.advance! }.to change(subject, :cursor)
+        expect(subject).to be_persisted
+      end
+    end
+
+    context 'when no more objects are available' do
+      before { Fabricate.times(2, :status) }
+
+      it 'sets `fulfilled` to `true`' do
+        expect { subject.advance! }.to change(subject, :fulfilled)
+          .from(false).to(true)
+        expect(subject).to be_persisted
+      end
+    end
+  end
 end
diff --git a/spec/models/fasp/subscription_spec.rb b/spec/models/fasp/subscription_spec.rb
index 493fe3e345..d51759d48f 100644
--- a/spec/models/fasp/subscription_spec.rb
+++ b/spec/models/fasp/subscription_spec.rb
@@ -3,5 +3,31 @@
 require 'rails_helper'
 
 RSpec.describe Fasp::Subscription do
-  pending "add some examples to (or delete) #{__FILE__}"
+  describe '#threshold=' do
+    subject { described_class.new }
+
+    it 'allows setting all threshold values at once' do
+      subject.threshold = {
+        'timeframe' => 30,
+        'shares' => 5,
+        'likes' => 8,
+        'replies' => 7,
+      }
+
+      expect(subject.threshold_timeframe).to eq 30
+      expect(subject.threshold_shares).to eq 5
+      expect(subject.threshold_likes).to eq 8
+      expect(subject.threshold_replies).to eq 7
+    end
+  end
+
+  describe '#timeframe_start' do
+    subject { described_class.new(threshold_timeframe: 45) }
+
+    it 'returns a Time representing the beginning of the timeframe' do
+      travel_to Time.zone.local(2025, 4, 7, 16, 40) do
+        expect(subject.timeframe_start).to eq Time.zone.local(2025, 4, 7, 15, 55)
+      end
+    end
+  end
 end