Changed VariableAccumulator so it can represent itself with null valu…

…es (#2816)

* Changed VariableAccumulator so it can repreent itself with null values - Collector.toMap will not allow null values

* Better test

src/main/java/graphql/normalized/VariableAccumulator.java

@@ -5,6 +5,7 @@
 import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -52,10 +53,11 @@ public List<VariableDefinition> getVariableDefinitions() {
      * @return the map of variable names to variable values
      */
     public Map<String, Object> getVariablesMap() {
-        return valueWithDefinitions.stream()
-                .collect(Collectors.toMap(
-                        variableWithDefinition -> variableWithDefinition.getDefinition().getName(),
-                        VariableValueWithDefinition::getValue
-                ));
+        Map<String, Object> map = new LinkedHashMap<>();
+        valueWithDefinitions.forEach(variableWithDefinition -> {
+            String name = variableWithDefinition.getDefinition().getName();
+            map.put(name, variableWithDefinition.getValue());
+        });
+        return map;
     }
 }

src/test/groovy/graphql/normalized/VariableAccumulatorTest.groovy

@@ -0,0 +1,46 @@
+package graphql.normalized
+
+import graphql.language.IntValue
+import graphql.language.NullValue
+import graphql.language.StringValue
+import graphql.language.TypeName
+import spock.lang.Specification
+
+class VariableAccumulatorTest extends Specification {
+
+    def alwaysTruePredicate = new VariablePredicate() {
+        @Override
+        boolean shouldMakeVariable(ExecutableNormalizedField executableNormalizedField, String argName, NormalizedInputValue normalizedInputValue) {
+            return true
+        }
+    }
+
+    def "can build itself handing null values"() {
+        when:
+        VariableAccumulator accumulator = new VariableAccumulator(alwaysTruePredicate)
+        accumulateData(accumulator)
+
+        def variablesMap = accumulator.getVariablesMap()
+        then:
+        variablesMap == [v0: "hello", v1: 666, v2: null, v3: null]
+    }
+
+    def "can build variable definitions"() {
+        when:
+        VariableAccumulator accumulator = new VariableAccumulator(alwaysTruePredicate)
+        accumulateData(accumulator)
+        def names = accumulator.getVariableDefinitions().collect { vd -> vd.name }
+        def typeNames = accumulator.getVariableDefinitions().collect { vd -> (vd.type as TypeName).name }
+
+        then:
+        names == ["v0", "v1", "v2", "v3"]
+        typeNames == ["String", "Int", "Int", "String"]
+    }
+
+    private void accumulateData(VariableAccumulator accumulator) {
+        accumulator.accumulateVariable(new NormalizedInputValue("String", StringValue.of("hello")))
+        accumulator.accumulateVariable(new NormalizedInputValue("Int", IntValue.of(666)))
+        accumulator.accumulateVariable(new NormalizedInputValue("Int", NullValue.of()))
+        accumulator.accumulateVariable(new NormalizedInputValue("String", null))
+    }
+}