add support for lists when using JsonFileSource.

Author: Max Xandeco

src/main/java/net/joshka/junit/json/params/JsonFileArgumentsProvider.java

@@ -1,5 +1,10 @@
 package net.joshka.junit.json.params;
 
+import static java.util.Arrays.stream;
+
+import java.util.Collection;
+import java.util.List;
+import javax.json.JsonValue.ValueType;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.ArgumentsProvider;
@@ -29,12 +34,9 @@ public class JsonFileArgumentsProvider implements AnnotationConsumer<JsonFileSou
         this.inputStreamProvider = inputStreamProvider;
     }
 
-    private static Stream<JsonValue> values(InputStream inputStream) {
+    private static JsonValue values(InputStream inputStream) {
         try (JsonReader reader = Json.createReader(inputStream)) {
-            JsonStructure structure = reader.read();
-            return structure.getValueType() == JsonValue.ValueType.ARRAY
-                    ? structure.asJsonArray().stream()
-                    : Stream.of(structure);
+            return reader.read();
         }
     }
 
@@ -45,10 +47,18 @@ public void accept(JsonFileSource jsonFileSource) {
 
     @Override
     public Stream<? extends Arguments> provideArguments(ExtensionContext context) {
-        return Arrays.stream(resources)
+        boolean isList = stream(context.getRequiredTestMethod().getParameterTypes())
+            .anyMatch(List.class::isAssignableFrom);
+        return stream(resources)
                 .map(resource -> openInputStream(context, resource))
-                .flatMap(JsonFileArgumentsProvider::values)
-                .map(Arguments::of);
+                .map(JsonFileArgumentsProvider::values)
+                .flatMap(json -> {
+                    if(json.getValueType() == ValueType.ARRAY && !isList){
+                        return json.asJsonArray().stream();
+                    }
+                    return Stream.of(json);
+                })
+            .map(Arguments::arguments);
     }
 
     private InputStream openInputStream(ExtensionContext context, String resource) {

src/test/java/net/joshka/junit/json/params/JsonFileArgumentsProviderTest.java

@@ -1,5 +1,8 @@
 package net.joshka.junit.json.params;
 
+import java.lang.reflect.Method;
+import java.util.List;
+import javax.json.JsonArray;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtensionContext;
@@ -71,13 +74,47 @@ void arrayOfStrings(JsonString string) {
         assertThat(string.getString()).startsWith("value");
     }
 
+    /**
+     * When passed <code>[{"key":"value1"},{"key","value2"}]</code>
+     * and argument is a JsonArray, test is executed only once.
+     * @param object the parsed JsonArray object
+     */
+    @ParameterizedTest
+    @JsonFileSource(resources = "/array-of-objects.json")
+    void jsonArray(JsonArray object) {
+        assertThat(object).hasSize(2);
+    }
+
+    /**
+     * When passed <code>[{"key":"value1"},{"key","value2"}]</code>
+     * and argument is a List, test is executed only once.
+     * @param object the parsed List object
+     */
+    @ParameterizedTest
+    @JsonFileSource(resources = "/array-of-objects.json")
+    void listJsonObject(List<JsonObject> object) {
+        assertThat(object).hasSize(2);
+    }
+
+    /**
+     * When passed <code>[{"key":"value1"},{"key","value2"}]</code>
+     * and argument is a List, test is executed only once.
+     * @param object the parsed List object
+     */
+    @ParameterizedTest
+    @JsonFileSource(resources = "/array-of-objects.json")
+    void listString(List<String> object) {
+        assertThat(object).hasSize(2);
+    }
+
     @Test
     @DisplayName("missing resource throws exception")
-    void missingResource() {
+    void missingResource() throws Exception {
         BiFunction<Class, String, InputStream> inputStreamProvider = (aClass, resource) -> null;
         ExtensionContext context = mock(ExtensionContext.class);
         JsonFileSource source = mock(JsonFileSource.class);
         when(source.resources()).thenReturn(new String[]{"not-found.json"});
+        when(context.getRequiredTestMethod()).thenReturn(this.getClass().getDeclaredMethod("missingResource"));
         JsonFileArgumentsProvider provider = new JsonFileArgumentsProvider(inputStreamProvider);
         provider.accept(source);