Moved ancillary files to extras/ (fixes #1011)

extras/tests/JsonObject/containsKey.cpp

@@ -0,0 +1,39 @@
+// ArduinoJson - arduinojson.org
+// Copyright Benoit Blanchon 2014-2019
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonObject::containsKey()") {
+  DynamicJsonDocument doc(4096);
+  JsonObject obj = doc.to<JsonObject>();
+  obj["hello"] = 42;
+
+  SECTION("returns true only if key is present") {
+    REQUIRE(false == obj.containsKey("world"));
+    REQUIRE(true == obj.containsKey("hello"));
+  }
+
+  SECTION("works with JsonObjectConst") {
+    JsonObjectConst cobj = obj;
+    REQUIRE(false == cobj.containsKey("world"));
+    REQUIRE(true == cobj.containsKey("hello"));
+  }
+
+  SECTION("returns false after remove()") {
+    obj.remove("hello");
+
+    REQUIRE(false == obj.containsKey("hello"));
+  }
+
+#ifdef HAS_VARIABLE_LENGTH_ARRAY
+  SECTION("key is a VLA") {
+    int i = 16;
+    char vla[i];
+    strcpy(vla, "hello");
+
+    REQUIRE(true == obj.containsKey(vla));
+  }
+#endif
+}