Allow multiple null ports (it means autogenerate) (#381)

src/Microsoft.Tye.Core/ConfigModel/ConfigApplication.cs

@@ -106,7 +106,7 @@ namespace Microsoft.Tye.ConfigModel
                         throw new TyeYamlException(CoreStrings.FormatMultipleBindingWithSameName("service"));
                     }
 
-                    if (service.Bindings.Count(o => o.Port == binding.Port) > 1)
+                    if (service.Bindings.Count(o => o.Port != null && o.Port == binding.Port) > 1)
                     {
                         throw new TyeYamlException(CoreStrings.FormatMultipleBindingWithSamePort("service"));
                     }

test/UnitTests/TyeDeserializationValidationTests.cs

@@ -171,6 +171,23 @@ services:
             Assert.Contains(CoreStrings.FormatMultipleBindingWithSamePort("service"), exception.Message);
         }
 
+        [Fact]
+        public void ServicesMustHaveUniqueNonNullPorts()
+        {
+            var input = @"
+services:
+  - name: app
+    bindings:
+      - protocol: http
+        name: a
+      - protocol: https
+        name: b";
+
+            using var parser = new YamlParser(input);
+            var app = parser.ParseConfigApplication();
+            app.Validate();
+        }
+
 
         [Theory]
         [InlineData("image", "executable")]