hasJsonPath("path.to.empty.array") will match, e.g return true

json-path-assert/README.md

@@ -80,3 +80,24 @@ Use typed matchers for specific JSON representations, if needed
 
     File json = ...
     assertThat(json, isJsonFile(withJsonPath("$..author")));
+
+---
+
+CAUTION: regarding the use of indefinite paths
+
+When using indefinite path expressions (e.g with wildcards '*'), the result will yield a list. Possibly an _empty_ list if no matching entries were found. If you want to assert that the list will actually contain something, make sure to express this explicitly, e.g checking for the size of the list.
+
+    // Given a JSON like this:
+    {
+      "items": []
+    }
+
+    // Both of these statements will succeed(!)
+    assertThat(json, hasJsonPath("$.items[*]"));
+    assertThat(json, hasJsonPath("$.items[*].name"));
+    
+    // Make sure to explicitly check for size if you want to catch this scenario as a failure
+    assertThat(json, hasJsonPath("$.items[*]", hasSize(greaterThan(0))));
+    
+    // However, checking for the existence of an array works fine, as is
+    assertThat(json, hasJsonPath("$.not_here[*]"));

json-path-assert/src/main/java/com/jayway/jsonpath/matchers/JsonPathMatchers.java

@@ -19,7 +19,7 @@ public class JsonPathMatchers {
 
     public static Matcher<? super Object> hasJsonPath(String jsonPath) {
         return describedAs("has json path %0",
-                hasJsonPath(jsonPath, not(anyOf(nullValue(), empty()))),
+                hasJsonPath(jsonPath, not(nullValue())),
                 jsonPath);
     }
 
@@ -53,7 +53,7 @@ public class JsonPathMatchers {
 
     public static Matcher<? super ReadContext> withJsonPath(JsonPath jsonPath) {
         return describedAs("with json path %0",
-                withJsonPath(jsonPath, not(anyOf(nullValue(), empty()))),
+                withJsonPath(jsonPath, not(nullValue())),
                 jsonPath.getPath());
     }
 

json-path-assert/src/test/java/com/jayway/jsonpath/matchers/JsonPathMatchersTest.java

@@ -73,16 +73,45 @@ public class JsonPathMatchersTest {
 
     @Test
     public void shouldMatchExistingJsonPath() {
-        assertThat(BOOKS_JSON, hasJsonPath("$.store.name"));
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.name"));        // string
-        assertThat(BOOKS_JSON, hasJsonPath("$.store.book[2].title"));
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.switch"));      // boolean
-        assertThat(BOOKS_JSON, hasJsonPath("$.store.book[*].author"));
+        assertThat(BOOKS_JSON, hasJsonPath("$.expensive"));         // number
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.bicycle"));     // object
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.truck"));       // empty object
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.book"));        // non-empty array
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.book[*]"));     // non-empty array
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.magazine"));    // empty array
+        assertThat(BOOKS_JSON, hasJsonPath("$.store.magazine[*]")); // empty array
     }
 
     @Test
     public void shouldMatchExistingJsonPathAlternative() {
-        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.name")));
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.name")));        // string
-        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.book[2].title")));
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.switch")));      // boolean
-        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.book[*].author")));
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.expensive")));         // number
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.bicycle")));     // object
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.truck")));       // empty object
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.book")));        // non-empty array
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.book[*]")));     // non-empty array
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.magazine")));    // empty array
+        assertThat(BOOKS_JSON, isJson(withJsonPath("$.store.magazine[*]"))); // empty array
+    }
+
+    @Test
+    public void shouldNotMatchNonExistentArrays() {
+        assertThat(BOOKS_JSON, not(hasJsonPath("$.store.not_here[*]")));
+    }
+
+    @Test
+    public void willMatchIndefiniteJsonPathsEvaluatedToEmptyLists() {
+        // This is just a test to demonstrate that wildcard paths
+        // will always match, regardless of result. This is because
+        // the evaluation of these expressions will at least return
+        // an empty list.
+        String json = "{\"items\": []}";
+        assertThat(json, hasJsonPath("$.items[*]"));
+        assertThat(json, hasJsonPath("$.items[*].name"));
+        assertThat(json, hasJsonPath("$.items[*]", hasSize(0)));
     }
 
     @Test
@@ -103,15 +132,17 @@ public class JsonPathMatchersTest {
     @Test
     public void shouldNotMatchNonExistingJsonPath() {
         assertThat(BOOKS_JSON, not(hasJsonPath("$.not_there")));
+        assertThat(BOOKS_JSON, not(hasJsonPath("$.store.not_there")));
+        assertThat(BOOKS_JSON, not(hasJsonPath("$.store.book[1].isbn")));
         assertThat(BOOKS_JSON, not(hasJsonPath("$.store.book[5].title")));
-        assertThat(BOOKS_JSON, not(hasJsonPath("$.store.book[*].not_there")));
     }
 
     @Test
     public void shouldNotMatchNonExistingJsonPathAlternative() {
         assertThat(BOOKS_JSON, not(isJson(withJsonPath("$.not_there"))));
+        assertThat(BOOKS_JSON, not(isJson(withJsonPath(("$.store.not_there")))));
+        assertThat(BOOKS_JSON, not(isJson(withJsonPath(("$.store.book[1].isbn")))));
         assertThat(BOOKS_JSON, not(isJson(withJsonPath("$.store.book[5].title"))));
-        assertThat(BOOKS_JSON, not(isJson(withJsonPath("$.store.book[*].not_there"))));
     }
 
     @Test

json-path-assert/src/test/java/com/jayway/jsonpath/matchers/WithJsonPathTest.java

@@ -9,6 +9,7 @@ import org.hamcrest.StringDescription;
 import org.junit.Test;
 
 import java.util.Collection;
+import java.util.List;
 
 import static com.jayway.jsonpath.JsonPath.compile;
 import static com.jayway.jsonpath.matchers.JsonPathMatchers.withJsonPath;
@@ -40,14 +41,14 @@ public class WithJsonPathTest {
     public void shouldNotMatchNonExistingJsonPath() {
         assertThat(BOOKS_JSON, not(withJsonPath(compile("$.not_there"))));
         assertThat(BOOKS_JSON, not(withJsonPath(compile("$.store.book[5].title"))));
-        assertThat(BOOKS_JSON, not(withJsonPath(compile("$.store.book[*].not_there"))));
+        assertThat(BOOKS_JSON, not(withJsonPath(compile("$.store.book[1].not_there"))));
     }
 
     @Test
     public void shouldNotMatchNonExistingStringJsonPath() {
         assertThat(BOOKS_JSON, not(withJsonPath("$.not_there")));
         assertThat(BOOKS_JSON, not(withJsonPath("$.store.book[5].title")));
-        assertThat(BOOKS_JSON, not(withJsonPath("$.store.book[*].not_there")));
+        assertThat(BOOKS_JSON, not(withJsonPath("$.store.book[1].not_there")));
     }
 
     @Test
@@ -92,7 +93,7 @@ public class WithJsonPathTest {
 
     @Test
     public void shouldMatchJsonPathEvaluatedToCollectionValue() {
-        assertThat(BOOKS_JSON, withJsonPath(compile("$.store.book[*].author"), instanceOf(Collection.class)));
+        assertThat(BOOKS_JSON, withJsonPath(compile("$.store.book[*].author"), instanceOf(List.class)));
         assertThat(BOOKS_JSON, withJsonPath(compile("$.store.book[*].author"), hasSize(4)));
         assertThat(BOOKS_JSON, withJsonPath(compile("$.store.book[*].author"), hasItem("Evelyn Waugh")));
         assertThat(BOOKS_JSON, withJsonPath(compile("$..book[2].title"), hasItem("Moby Dick")));

json-path-assert/src/test/resources/books.json

@@ -1,6 +1,9 @@
 {
   "store": {
     "name": "Little Shop",
+    "switch": true,
+    "magazine": [],
+    "truck": {},
     "book": [
       {
         "category": "reference",