feat: Add malysis cache implementation with proxy flow integration (#346)

* feat: Add malysis cache implementation with proxy flow integration

* fix: Code review fixes

analyzer/malysis_cache_analyzer_test.go

@@ -0,0 +1,85 @@
+package analyzer
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	packagev1 "buf.build/gen/go/safedep/api/protocolbuffers/go/safedep/messages/package/v1"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type fakeCache struct {
+	getResult *PackageVersionAnalysisResult
+	getOK     bool
+	getErr    error
+	setErr    error
+	setCalls  int
+}
+
+func (f *fakeCache) Get(context.Context, *packagev1.PackageVersion) (*PackageVersionAnalysisResult, bool, error) {
+	return f.getResult, f.getOK, f.getErr
+}
+func (f *fakeCache) Set(context.Context, *packagev1.PackageVersion, *PackageVersionAnalysisResult) error {
+	f.setCalls++
+	return f.setErr
+}
+
+type fakeAnalyzer struct {
+	result    *PackageVersionAnalysisResult
+	err       error
+	callCount int
+}
+
+func (f *fakeAnalyzer) Name() string { return "fake" }
+func (f *fakeAnalyzer) Analyze(context.Context, *packagev1.PackageVersion) (*PackageVersionAnalysisResult, error) {
+	f.callCount++
+	return f.result, f.err
+}
+
+func TestMalysisCachingAnalyzer_Hit(t *testing.T) {
+	cached := &PackageVersionAnalysisResult{Action: ActionAllow, AnalysisID: "cached"}
+	next := &fakeAnalyzer{}
+	a := newMalysisCachingAnalyzer(next, &fakeCache{getResult: cached, getOK: true})
+
+	got, err := a.Analyze(context.Background(), &packagev1.PackageVersion{})
+	require.NoError(t, err)
+	assert.Equal(t, "cached", got.AnalysisID)
+	assert.Equal(t, 0, next.callCount, "hit must not delegate")
+}
+
+func TestMalysisCachingAnalyzer_MissDelegatesAndSets(t *testing.T) {
+	live := &PackageVersionAnalysisResult{Action: ActionAllow, AnalysisID: "live"}
+	next := &fakeAnalyzer{result: live}
+	fc := &fakeCache{}
+	a := newMalysisCachingAnalyzer(next, fc)
+
+	got, err := a.Analyze(context.Background(), &packagev1.PackageVersion{})
+	require.NoError(t, err)
+	assert.Equal(t, "live", got.AnalysisID)
+	assert.Equal(t, 1, next.callCount)
+	assert.Equal(t, 1, fc.setCalls)
+}
+
+func TestMalysisCachingAnalyzer_FailSoft(t *testing.T) {
+	live := &PackageVersionAnalysisResult{Action: ActionAllow, AnalysisID: "live"}
+	next := &fakeAnalyzer{result: live}
+	// Get error => treat as miss and delegate; Set error => still return result.
+	a := newMalysisCachingAnalyzer(next, &fakeCache{getErr: errors.New("boom"), setErr: errors.New("boom")})
+
+	got, err := a.Analyze(context.Background(), &packagev1.PackageVersion{})
+	require.NoError(t, err)
+	assert.Equal(t, "live", got.AnalysisID)
+	assert.Equal(t, 1, next.callCount)
+}
+
+func TestMalysisCachingAnalyzer_AnalyzeErrorNotCached(t *testing.T) {
+	next := &fakeAnalyzer{err: errors.New("network")}
+	fc := &fakeCache{}
+	a := newMalysisCachingAnalyzer(next, fc)
+
+	_, err := a.Analyze(context.Background(), &packagev1.PackageVersion{})
+	require.Error(t, err)
+	assert.Equal(t, 0, fc.setCalls, "errored analysis must not be cached")
+}