diff --git a/test/test_cache_store.rb b/test/test_cache_store.rb
new file mode 100644
index 0000000..11884a3
--- /dev/null
+++ b/test/test_cache_store.rb
@@ -0,0 +1,116 @@
+require 'minitest/autorun'
+require 'prism'
+
+class CacheStoreTest < Minitest::Test
+  def setup
+    @store = Prism::Cache::MemoryStore.new
+  end
+
+  def test_write_then_read_round_trips
+    @store.write('key', 'value')
+    assert_equal 'value', @store.read('key')
+  end
+
+  def test_read_of_missing_key_is_nil
+    assert_nil @store.read('missing')
+  end
+
+  def test_keys_are_coerced_to_string
+    @store.write(:sym_key, 'value')
+    assert_equal 'value', @store.read('sym_key')
+  end
+
+  def test_fetch_computes_and_stores_on_miss
+    calls = 0
+    3.times { @store.fetch('k') { calls += 1; 'computed' } }
+    assert_equal 1, calls
+  end
+
+  def test_fetch_returns_existing_value_without_yielding_on_hit
+    @store.write('k', 'preset')
+    result = @store.fetch('k') { raise 'must not be called' }
+    assert_equal 'preset', result
+  end
+
+  def test_delete_removes_the_entry
+    @store.write('k', 'v')
+    assert @store.delete('k')
+    assert_nil @store.read('k')
+  end
+
+  def test_delete_of_missing_key_returns_falsey
+    refute @store.delete('missing')
+  end
+
+  def test_exist_reflects_presence
+    refute @store.exist?('k')
+    @store.write('k', 'v')
+    assert @store.exist?('k')
+  end
+
+  def test_clear_empties_the_store
+    @store.write('a', 1)
+    @store.write('b', 2)
+    @store.clear
+    assert_equal 0, @store.size
+  end
+
+  def test_expires_in_makes_the_entry_unreadable_afterwards
+    @store.write('k', 'v', expires_in: 0)
+    sleep 0.01
+    assert_nil @store.read('k')
+  end
+
+  def test_delete_matched_removes_keys_matching_a_regexp
+    @store.write('posts/1', 'a')
+    @store.write('posts/2', 'b')
+    @store.write('users/1', 'c')
+    @store.delete_matched(/\Aposts\//)
+    assert_nil @store.read('posts/1')
+    assert_nil @store.read('posts/2')
+    assert_equal 'c', @store.read('users/1')
+  end
+
+  def test_default_store_is_a_memory_store_singleton
+    assert_same Prism::Cache.store, Prism::Cache.store
+    assert_instance_of Prism::Cache::MemoryStore, Prism::Cache.store
+  end
+
+  def test_unbounded_store_never_evicts
+    store = Prism::Cache::MemoryStore.new
+    50.times { |i| store.write("k#{i}", i) }
+    assert_equal 50, store.size
+  end
+
+  def test_max_size_evicts_the_least_recently_used_entry_on_write
+    store = Prism::Cache::MemoryStore.new(max_size: 2)
+    store.write('a', 1)
+    store.write('b', 2)
+    store.write('c', 3)
+    assert_equal 2, store.size
+    assert_nil store.read('a')
+    assert_equal 2, store.read('b')
+    assert_equal 3, store.read('c')
+  end
+
+  def test_reading_a_key_protects_it_from_eviction
+    store = Prism::Cache::MemoryStore.new(max_size: 2)
+    store.write('a', 1)
+    store.write('b', 2)
+    store.read('a') # bump 'a' to most-recently-used, 'b' is now the LRU one
+    store.write('c', 3)
+    assert_equal 1, store.read('a')
+    assert_nil store.read('b')
+    assert_equal 3, store.read('c')
+  end
+
+  def test_rewriting_an_existing_key_does_not_grow_the_store
+    store = Prism::Cache::MemoryStore.new(max_size: 2)
+    store.write('a', 1)
+    store.write('b', 2)
+    store.write('a', 'updated')
+    assert_equal 2, store.size
+    assert_equal 'updated', store.read('a')
+    assert_equal 2, store.read('b')
+  end
+end
diff --git a/test/test_cli_assets_precompile.rb b/test/test_cli_assets_precompile.rb
new file mode 100644
index 0000000..2b2be2e
--- /dev/null
+++ b/test/test_cli_assets_precompile.rb
@@ -0,0 +1,58 @@
+require 'minitest/autorun'
+require 'prism'
+require 'tmpdir'
+require 'fileutils'
+require 'stringio'
+
+class CliAssetsPrecompileTest < Minitest::Test
+  def setup
+    @dir = Dir.mktmpdir('prism-cli-assets')
+    @cli = Prism::Cli.new(@dir)
+    @source = File.join(@dir, 'app', 'assets')
+    @output = File.join(@dir, 'public', 'assets')
+    FileUtils.mkdir_p(File.join(@source, 'stylesheets'))
+    File.write(File.join(@source, 'stylesheets', 'application.css'), 'body { color: red; }')
+  end
+
+  def teardown
+    FileUtils.remove_entry(@dir)
+  end
+
+  def test_precompiles_without_booting_an_application
+    manifest = @cli.assets_precompile(['--source=app/assets', '--output=public/assets'], out: StringIO.new)
+    logical = manifest.to_h.keys
+    assert_equal ['stylesheets/application.css'], logical
+    fingerprinted = manifest.lookup('stylesheets/application.css')
+    assert_match(/\Astylesheets\/application-[0-9a-f]{8}\.css\z/, fingerprinted)
+    assert File.exist?(File.join(@output, fingerprinted))
+    assert File.exist?(File.join(@output, 'manifest.json'))
+  end
+
+  def test_prints_a_summary_to_the_given_output
+    out = StringIO.new
+    @cli.assets_precompile(['--source=app/assets', '--output=public/assets'], out: out)
+    assert_match(/compiled 1 file\(s\) into/, out.string)
+  end
+
+  def test_recompiling_unchanged_content_reproduces_the_same_fingerprint_and_removes_nothing_stale
+    first = @cli.assets_precompile(['--source=app/assets', '--output=public/assets'], out: StringIO.new)
+    second = @cli.assets_precompile(['--source=app/assets', '--output=public/assets'], out: StringIO.new)
+    assert_equal first.to_h, second.to_h
+  end
+
+  def test_raises_usage_error_without_required_options
+    assert_raises(Prism::Cli::UsageError) { @cli.assets_precompile([]) }
+    assert_raises(Prism::Cli::UsageError) { @cli.assets_precompile(['--source=app/assets']) }
+  end
+
+  def test_run_dispatches_the_assets_colon_precompile_command
+    original_stdout = $stdout
+    captured = StringIO.new
+    $stdout = captured
+    @cli.run(['assets:precompile', '--source=app/assets', '--output=public/assets'])
+  ensure
+    $stdout = original_stdout
+    assert_match(/compiled 1 file\(s\)/, captured.string)
+    assert File.exist?(File.join(@output, 'manifest.json'))
+  end
+end