Deduplicate static strings

extras/tests/JsonDocument/MemberProxy.cpp

@@ -382,6 +382,24 @@ TEST_CASE("Deduplicate keys") {
                              Allocate(sizeofString("example")),
                          });
   }
+
+  SECTION("string literals") {
+    doc[0]["example"] = 1;
+    doc[1]["example"] = 2;
+    doc.shrinkToFit();
+
+    const char* key1 = doc[0].as<JsonObject>().begin()->key().c_str();
+    const char* key2 = doc[1].as<JsonObject>().begin()->key().c_str();
+    CHECK(key1 == key2);
+
+    REQUIRE(spy.log() ==
+            AllocatorLog{
+                Allocate(sizeofPool()),
+                Allocate(sizeofStaticStringPool()),
+                Reallocate(sizeofPool(), sizeofPool(6)),
+                Reallocate(sizeofStaticStringPool(), sizeofStaticStringPool(1)),
+            });
+  }
 }
 
 TEST_CASE("MemberProxy under memory constraints") {

extras/tests/ResourceManager/saveString.cpp

@@ -19,6 +19,25 @@ static StringNode* saveString(ResourceManager& resources, const char* s,
   return resources.saveString(adaptString(s, n));
 }
 
+TEST_CASE("ResourceManager::saveStaticString()") {
+  SpyingAllocator spy;
+  ResourceManager resources(&spy);
+
+  auto a = resources.saveStaticString("hello");
+  auto b = resources.saveStaticString("world");
+  REQUIRE(a != b);
+
+  auto c = resources.saveStaticString("hello");
+  REQUIRE(a == c);
+
+  resources.shrinkToFit();
+  REQUIRE(spy.log() ==
+          AllocatorLog{
+              Allocate(sizeofStaticStringPool()),
+              Reallocate(sizeofStaticStringPool(), sizeofStaticStringPool(2)),
+          });
+}
+
 TEST_CASE("ResourceManager::saveString()") {
   ResourceManager resources;