Required some size to exist on banner requests (prebid#646)

* Required some size to exist on banner requests.

* Added more tests. Fixed the code a bit.

endpoints/openrtb2/auction.go

@@ -355,6 +355,11 @@ func validateBanner(banner *openrtb.Banner, impIndex int) error {
 		return fmt.Errorf("request.imp[%d].banner uses unsupported property: \"hmax\". Use the \"format\" array instead.", impIndex)
 	}
 
+	hasRootSize := banner.H != nil && banner.W != nil && *banner.H > 0 && *banner.W > 0
+	if !hasRootSize && len(banner.Format) == 0 {
+		return fmt.Errorf("request.imp[%d].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.", impIndex)
+	}
+
 	for fmtIndex, format := range banner.Format {
 		if err := validateFormat(&format, impIndex, fmtIndex); err != nil {
 			return err

endpoints/openrtb2/sample-requests/invalid-whole/banner-h-only.json

@@ -0,0 +1,22 @@
+{
+  "message": "Invalid request: request.imp[0].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.\n",
+  "requestPayload": {
+    "id":"req-id",
+    "site": {
+      "id": "some-site"
+    },
+    "imp": [
+      {
+        "id":"imp-id",
+        "banner":{
+          "h": 300
+        },
+        "ext": {
+          "appnexus": {
+            "placementId": 10433394
+          }
+        }
+      }
+    ]
+  }
+}

endpoints/openrtb2/sample-requests/invalid-whole/banner-h-zero.json

@@ -0,0 +1,23 @@
+{
+  "message": "Invalid request: request.imp[0].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.\n",
+  "requestPayload": {
+    "id":"req-id",
+    "site": {
+      "id": "some-site"
+    },
+    "imp": [
+      {
+        "id":"imp-id",
+        "banner":{
+          "h": 0,
+          "w": 250
+        },
+        "ext": {
+          "appnexus": {
+            "placementId": 10433394
+          }
+        }
+      }
+    ]
+  }
+}

endpoints/openrtb2/sample-requests/invalid-whole/banner-w-only.json

@@ -0,0 +1,22 @@
+{
+  "message": "Invalid request: request.imp[0].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.\n",
+  "requestPayload": {
+    "id":"req-id",
+    "site": {
+      "id": "some-site"
+    },
+    "imp": [
+      {
+        "id":"imp-id",
+        "banner":{
+          "w": 50
+        },
+        "ext": {
+          "appnexus": {
+            "placementId": 10433394
+          }
+        }
+      }
+    ]
+  }
+}

endpoints/openrtb2/sample-requests/invalid-whole/banner-w-zero.json

@@ -0,0 +1,23 @@
+{
+  "message": "Invalid request: request.imp[0].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.\n",
+  "requestPayload": {
+    "id":"req-id",
+    "site": {
+      "id": "some-site"
+    },
+    "imp": [
+      {
+        "id": "imp-id",
+        "banner": {
+          "h": 300,
+          "w": 0
+        },
+        "ext": {
+          "appnexus": {
+            "placementId": 10433394
+          }
+        }
+      }
+    ]
+  }
+}

endpoints/openrtb2/sample-requests/invalid-whole/format-empty-array.json

@@ -1,12 +1,20 @@
 {
-  "message": "Invalid request: request.imp[0].ext is required\n",
+  "message": "Invalid request: request.imp[0].banner has no sizes. Define \"w\" and \"h\", or include \"format\" elements.\n",
   "requestPayload": {
     "id":"req-id",
+    "site": {
+      "id": "some-site"
+    },
     "imp": [
       {
-        "id":"imp-id",
-        "banner":{
-          "format":[]
+        "id": "imp-id",
+        "banner": {
+          "format": []
+        },
+        "ext": {
+          "appnexus": {
+            "placementId": 10433394
+          }
         }
       }
     ]