Fix broken build restrictions

In f3ac9e9669 the fail condition was broken causing it to allow building on restricted areas.

Add a test to ensure correct behavior for this case.

Reported by: @wowgetoffyourcellphone
Pull Request: #8021

binaries/data/mods/public/simulation/components/BuildRestrictions.js

@@ -151,23 +151,25 @@ BuildRestrictions.prototype.CheckPlacement = function()
 		var ret = cmpObstruction.CheckFoundation(passClassName, false);
 	}
 
-	if (ret != "success")
+	if (ret !== "success")
 	{
 		switch (ret)
 		{
-		case "fail_error":
-		case "fail_no_obstruction":
-			error("CheckPlacement: Error returned from CheckFoundation");
-			break;
 		case "fail_obstructs_foundation":
 			result.message = markForTranslation("%(name)s cannot be built on another building or resource");
 			break;
 		case "fail_terrain_class":
 			// TODO: be more specific and/or list valid terrain?
 			result.message = markForTranslation("%(name)s cannot be built on invalid terrain");
+			break;
+		case "fail_error":
+		case "fail_no_obstruction":
 		default:
-			return result; // Fail
+			error(`CheckPlacement: Error returned from CheckFoundation. Got reason: '${ret}'`);
+			break;
 		}
+
+		return result;
 	}
 
 	// Check territory restrictions

binaries/data/mods/public/simulation/components/tests/test_BuildRestrictions.js

@@ -0,0 +1,30 @@
+Engine.LoadComponentScript("interfaces/BuildRestrictions.js");
+Engine.LoadComponentScript("BuildRestrictions.js");
+
+{
+	const entity = 10;
+	const QueryOwnerInterface = () => ({
+		"GetPlayerID": () => 1,
+		"IsAI": () => false
+	});
+	Engine.RegisterGlobal("QueryOwnerInterface", QueryOwnerInterface);
+	const cmpBuildRestrictions = ConstructComponent(entity, "BuildRestrictions", {
+		"PlacementType": "land"
+	});
+
+	AddMock(SYSTEM_ENTITY, IID_RangeManager, {
+		"GetLosVisibility": (_, __) => "visible",
+		"GetEntitiesByPlayer": () => []
+	});
+
+	AddMock(entity, IID_Ownership, {
+		"GetOwner": () => 1
+	});
+
+	AddMock(entity, IID_Obstruction, {
+		"CheckFoundation": () => "fail_obstructs_foundation"
+	});
+
+	const result = cmpBuildRestrictions.CheckPlacement();
+	TS_ASSERT_EQUALS(result.success, false);
+}