Add info about config false leafs to describe

Change-Id: Ie256f11617a48ec6dfa913cae1484550e9ec8664
diff --git a/tests/yang.cpp b/tests/yang.cpp
index 941586d..0f8dc8f 100644
--- a/tests/yang.cpp
+++ b/tests/yang.cpp
@@ -354,6 +354,18 @@
         }
     }
 
+    leaf clockSpeed {
+        type int64;
+        config false;
+    }
+
+    container systemStats {
+        config false;
+        leaf upTime {
+            type uint64;
+        }
+    }
+
 })";
 
 namespace std {
@@ -762,7 +774,9 @@
                        "example-schema:portSettings",
                        "example-schema:portMapping",
                        "example-schema:activeMappedPort",
-                       "example-schema:activePort"};
+                       "example-schema:activePort",
+                       "example-schema:clockSpeed",
+                       "example-schema:systemStats"};
             }
 
             SECTION("example-schema:a")
@@ -916,6 +930,14 @@
         {
             REQUIRE(ys.leafrefPath("/example-schema:activeNumber") == "/example-schema:_list/number");
         }
+
+        SECTION("isConfig")
+        {
+            REQUIRE(ys.isConfig("/example-schema:leafInt32"));
+            REQUIRE_FALSE(ys.isConfig("/example-schema:clockSpeed"));
+            REQUIRE_FALSE(ys.isConfig("/example-schema:systemStats"));
+            REQUIRE_FALSE(ys.isConfig("/example-schema:systemStats/upTime"));
+        }
     }
 
     SECTION("negative")