diff --git a/spec/lib/cache_spec.rb b/spec/lib/cache_spec.rb
new file mode 100644
index 000000000..e54208ca2
--- /dev/null
+++ b/spec/lib/cache_spec.rb
@@ -0,0 +1,94 @@
+require 'rails_helper'
+
+RSpec.describe Cache do
+  describe '.get' do
+    before { allow(Rails.cache).to receive(:read) }
+
+    it 'wraps Rails.cache.read' do
+      Cache.get('foo')
+
+      expect(Rails.cache).to have_received(:read).with('foo')
+    end
+
+    context 'with a non-string argument' do
+      it 'passes a string' do
+        Cache.get(:foo)
+
+        expect(Rails.cache).to have_received(:read).with('foo')
+      end
+    end
+  end
+
+  describe '.write' do
+    it 'stores string values' do
+      expect { Cache.write('123', 'some value') }
+        .to change { Cache.get('123') }.to('some value')
+    end
+
+    it 'stores hash values' do
+      expect { Cache.write('123', { key: 'some value' }) }
+        .to change { Cache.get('123') }.to({ key: 'some value' })
+    end
+
+    it 'overwrites previous values' do
+      Cache.write('123', 'some value')
+
+      expect { Cache.write('123', { key: 'some value' }) }
+        .to change { Cache.get('123') }.to({ key: 'some value' })
+    end
+
+    it 'stores hash values with non-ASCII content' do
+      expect { Cache.write('123', { key: 'some valueöäüß' }) }
+        .to change { Cache.get('123') }.to({ key: 'some valueöäüß' })
+    end
+
+    it 'defaults to expires_in: 7.days' do
+      Cache.write('123', 'some value')
+
+      expect { travel 7.days }.not_to change { Cache.get('123') }
+      expect { travel 1.second }.to change { Cache.get('123') }.to(nil)
+    end
+
+    it 'accepts a custom :expires_in option' do
+      Cache.write('123', 'some value', expires_in: 3.seconds)
+
+      expect { travel 4.seconds }.to change { Cache.get('123') }.to(nil)
+    end
+  end
+
+  describe '.delete' do
+    it 'deletes stored values' do
+      Cache.write('123', 'some value')
+
+      expect { Cache.delete('123') }
+        .to change { Cache.get('123') }.to(nil)
+    end
+
+    it 'is idempotent' do
+      Cache.write('123', 'some value')
+      Cache.delete('123')
+
+      expect { Cache.delete('123') }.not_to raise_error
+    end
+  end
+
+  describe '.clear' do
+    it 'deletes all stored values' do
+      Cache.write('123', 'some value')
+      Cache.write('456', 'some value')
+
+      # rubocop:disable Layout/MultilineMethodCallIndentation
+      expect { Cache.clear }
+        .to change { Cache.get('123') }.to(nil)
+        .and change { Cache.get('456') }.to(nil)
+      # rubocop:enable Layout/MultilineMethodCallIndentation
+    end
+
+    it 'is idempotent' do
+      Cache.write('123', 'some value')
+      Cache.clear
+
+      expect { Cache.delete('123') }.not_to raise_error
+    end
+  end
+end
diff --git a/test/unit/cache_test.rb b/test/unit/cache_test.rb
deleted file mode 100644
index d1a0facda..000000000
--- a/test/unit/cache_test.rb
+++ /dev/null
@@ -1,57 +0,0 @@
-require 'test_helper'
-
-class CacheTest < ActiveSupport::TestCase
-  test 'cache' do
-
-    # test 1
-    Cache.write('123', 'some value')
-    cache = Cache.get('123')
-    assert_equal(cache, 'some value')
-
-    Cache.write('123', { key: 'some value' })
-    cache = Cache.get('123')
-    assert_equal(cache, { key: 'some value' })
-
-    # test 2
-    Cache.write('123', { key: 'some valueöäüß' })
-    cache = Cache.get('123')
-    assert_equal(cache, { key: 'some valueöäüß' })
-
-    # test 3
-    Cache.delete('123')
-    cache = Cache.get('123')
-    assert_nil(cache)
-
-    # test 4
-    Cache.write('123', { key: 'some valueöäüß2' })
-    cache = Cache.get('123')
-    assert_equal(cache, { key: 'some valueöäüß2' })
-
-    Cache.delete('123')
-    cache = Cache.get('123')
-    assert_nil(cache)
-
-    # test 5
-    Cache.clear
-    cache = Cache.get('123')
-    assert_nil(cache)
-
-    Cache.delete('123')
-    cache = Cache.get('123')
-    assert_nil(cache)
-
-    # test 6
-    Cache.write('123', { key: 'some valueöäüß2' }, expires_in: 3.seconds)
-    travel 5.seconds
-    cache = Cache.get('123')
-    assert_nil(cache)
-  end
-
-  # verify if second cache write overwrite first one
-  test 'cache reset' do
-    Cache.write('some_reset_key', 123)
-    Cache.write('some_reset_key', 12_356)
-    cache = Cache.get('some_reset_key')
-    assert_equal(cache, 12_356, 'verify')
-  end
-end