Adding Document Decoding Errors for some common problems

Tests/JSONAPITests/ResourceObject/ResourceObjectDecodingErrorTests.swift

@@ -287,6 +287,30 @@ extension ResourceObjectDecodingErrorTests {
     }
 }
 
+// MARK: - JSON:API Type
+extension ResourceObjectDecodingErrorTests {
+    func test_wrongType() {
+        XCTAssertThrowsError(try testDecoder.decode(
+            TestEntity2.self,
+            from: entity_is_wrong_type
+        )) { error in
+            XCTAssertEqual(
+                error as? ResourceObjectDecodingError,
+                ResourceObjectDecodingError(
+                    subjectName: "self",
+                    cause: .jsonTypeMismatch(expectedType: "fourteenth_test_entities", foundType: "not_correct_type"),
+                    location: .type
+                )
+            )
+
+            XCTAssertEqual(
+                (error as? ResourceObjectDecodingError)?.description,
+                #"found JSON:API type "not_correct_type" but expected "fourteenth_test_entities""#
+            )
+        }
+    }
+}
+
 // MARK: - Test Types
 extension ResourceObjectDecodingErrorTests {
     enum TestEntityType: ResourceObjectDescription {

Tests/JSONAPITests/ResourceObject/stubs/ResourceObjectStubs.swift

@@ -533,6 +533,17 @@ let entity_attribute_is_wrong_type3 = """
 }
 """.data(using: .utf8)!
 
+let entity_is_wrong_type = """
+{
+    "id": "1",
+    "type": "not_correct_type",
+    "attributes": {
+        "required": "hello",
+        "yetAnother": 101
+    }
+}
+""".data(using: .utf8)!
+
 let entity_attributes_entirely_missing = """
 {
     "id": "1",