distributed-cache: Spring Cache abstraction over Hazelcast, Infinispan and Redis (post 29)

2026-10-15 02:30:04 +00:00
parent 565ca61814
commit 8c77a744e0
18 changed files with 472 additions and 1 deletions
@@ -0,0 +1,70 @@
+package com.ankurm.distributedcache;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * The same two behaviours, asserted identically, against whichever
+ * CacheManager the active Spring profile wired up. That's deliberate:
+ * the point of the Spring Cache abstraction is that ExchangeRateLookupService
+ * and this test never change when the backend does - only the
+ * subclass's @ActiveProfiles (and, for Redis, the container) changes.
+ *
+ * ExchangeRateLookupService's callCount() is a singleton counter shared
+ * across every @Test method in a subclass's Spring context (JUnit does
+ * not create a fresh context per test method), so each test reads the
+ * counter before and after its own calls and asserts the *delta* rather
+ * than an absolute value - that way test execution order inside one
+ * class can never affect the result.
+ */
+abstract class CacheHitAndEvictionContractTest {
+
+    @Autowired
+    ExchangeRateLookupService service;
+
+    abstract String backendName();
+
+    @Test
+    void secondCallForSameKeyIsServedFromCache() {
+        int before = service.callCount();
+
+        service.rateFor("USD/INR");
+        int afterFirstCall = service.callCount();
+
+        service.rateFor("USD/INR");
+        int afterSecondCall = service.callCount();
+
+        Transcript t = new Transcript("29-" + backendName() + "-cache-hit.txt");
+        t.line("backend=%s", backendName());
+        t.line("rateFor(\"USD/INR\") call 1 -> method body ran, callCount %d -> %d", before, afterFirstCall);
+        t.line("rateFor(\"USD/INR\") call 2 -> served from cache, callCount stays %d", afterSecondCall);
+        t.write();
+
+        assertThat(afterFirstCall).isEqualTo(before + 1);
+        assertThat(afterSecondCall).isEqualTo(afterFirstCall);
+    }
+
+    @Test
+    void evictingAKeyForcesTheNextCallToRecompute() {
+        int before = service.callCount();
+
+        service.rateFor("USD/EUR");
+        int afterFirstCall = service.callCount();
+
+        service.evict("USD/EUR");
+        service.rateFor("USD/EUR");
+        int afterEvictAndRecall = service.callCount();
+
+        Transcript t = new Transcript("29-" + backendName() + "-cache-evict.txt");
+        t.line("backend=%s", backendName());
+        t.line("rateFor(\"USD/EUR\") call 1 -> method body ran, callCount %d -> %d", before, afterFirstCall);
+        t.line("evict(\"USD/EUR\") then rateFor(\"USD/EUR\") again -> method body ran again, callCount %d -> %d",
+                afterFirstCall, afterEvictAndRecall);
+        t.write();
+
+        assertThat(afterFirstCall).isEqualTo(before + 1);
+        assertThat(afterEvictAndRecall).isEqualTo(afterFirstCall + 1);
+    }
+}