Add tests

service/cachemdw/middleware.go

@@ -14,6 +14,10 @@ type cacheContextKey string
 
 const (
 	CachedContextKey cacheContextKey = "X-KAVA-PROXY-CACHED"
+
+	CacheHeaderKey       = "X-Cache"
+	CacheHitHeaderValue  = "HIT"
+	CacheMissHeaderValue = "MISS"
 )
 
 func (c *ServiceCache) Middleware(
@@ -51,6 +55,7 @@ func (c *ServiceCache) respond(
 	r *http.Request,
 	cachedQueryResponse []byte,
 ) {
+	w.Header().Add(CacheHeaderKey, CacheHitHeaderValue)
 	w.Header().Add("Content-Type", "application/json")
 	_, err := w.Write(cachedQueryResponse)
 	if err != nil {
@@ -68,6 +73,8 @@ func (c *ServiceCache) respondAndCache(
 	r *http.Request,
 	decodedReq *decode.EVMRPCRequestEnvelope,
 ) {
+	w.Header().Add(CacheHeaderKey, CacheMissHeaderValue)
+
 	recorder := httptest.NewRecorder()
 	next.ServeHTTP(recorder, r.WithContext(uncachedContext))
 	result := recorder.Result()
@@ -95,3 +102,8 @@ func (c *ServiceCache) respondAndCache(
 		c.Logger.Error().Msg(fmt.Sprintf("can't validate and cache response: %v", err))
 	}
 }
+
+func IsRequestCached(ctx context.Context) bool {
+	cached, ok := ctx.Value(CachedContextKey).(bool)
+	return ok && cached
+}

service/cachemdw/middleware_test.go

@@ -0,0 +1,94 @@
+package cachemdw
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/kava-labs/kava-proxy-service/clients/cache"
+	"github.com/kava-labs/kava-proxy-service/decode"
+	"github.com/kava-labs/kava-proxy-service/logging"
+	"github.com/kava-labs/kava-proxy-service/service"
+)
+
+func TestServiceCacheMiddleware(t *testing.T) {
+	logger, err := logging.New("TRACE")
+	require.NoError(t, err)
+
+	inMemoryCache := cache.NewInMemoryCache()
+	evmClient := NewMockEVMClient()
+	cacheTTL := time.Duration(0) // TTL: no expiry
+
+	serviceCache := NewServiceCache(inMemoryCache, evmClient, cacheTTL, service.DecodedRequestContextKey, &logger)
+
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !IsRequestCached(r.Context()) {
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(testEVMQueries[TestRequestEthBlockByNumberSpecific].ResponseBody))
+		}
+	})
+
+	t.Run("cache miss", func(t *testing.T) {
+		req := createTestHttpRequest(
+			t,
+			"https://api.kava.io:8545/thisshouldntshowup",
+			TestRequestEthBlockByNumberSpecific,
+		)
+		resp := httptest.NewRecorder()
+
+		serviceCache.Middleware(handler).ServeHTTP(resp, req)
+
+		require.Equal(t, http.StatusOK, resp.Code)
+		require.JSONEq(t, testEVMQueries[TestRequestEthBlockByNumberSpecific].ResponseBody, resp.Body.String())
+		require.Equal(t, CacheMissHeaderValue, resp.Header().Get(CacheHeaderKey))
+
+		cacheItems := inMemoryCache.GetAll(context.Background())
+		require.Len(t, cacheItems, 2)
+		require.Contains(t, cacheItems, "chain:api.kava.io:8545")
+		require.Contains(t, cacheItems, "query:1:0x5236d50a560cff0174f14be10bd00a21e8d73e89a200fbd219769b6aee297131")
+	})
+
+	t.Run("cache hit", func(t *testing.T) {
+		req := createTestHttpRequest(
+			t,
+			"https://api.kava.io:8545/thisshouldntshowup",
+			TestRequestEthBlockByNumberSpecific,
+		)
+		resp := httptest.NewRecorder()
+
+		serviceCache.Middleware(handler).ServeHTTP(resp, req)
+
+		require.Equal(t, http.StatusOK, resp.Code)
+		require.JSONEq(t, testEVMQueries[TestRequestEthBlockByNumberSpecific].ResponseBody, resp.Body.String())
+		require.Equal(t, CacheHitHeaderValue, resp.Header().Get(CacheHeaderKey))
+	})
+}
+
+func createTestHttpRequest(
+	t *testing.T,
+	url string,
+	reqName testReqName,
+) *http.Request {
+	t.Helper()
+
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	require.NoError(t, err)
+
+	decodedReq, err := decode.DecodeEVMRPCRequest(
+		[]byte(testEVMQueries[reqName].RequestBody),
+	)
+	require.NoError(t, err)
+
+	decodedReqCtx := context.WithValue(
+		req.Context(),
+		service.DecodedRequestContextKey,
+		decodedReq,
+	)
+	req = req.WithContext(decodedReqCtx)
+
+	return req
+}