- #964
- compute `ModelMetadata.Order` based on `[Display]` attribute
- property affects e.g. `@Html.DisplayFor()` generation for complex objects
- also affects order of messages in validation summaries
- test new scenarios involving `ModelMetadata.Order`
- per-property `ModelMetadata` and related tests
- validation and `HtmlHelper` tests
- add `HtmlHelperValidationSummaryTest` (which touches on #453)
- update ModelBinding functional test to show use of `[Display(Order = x)]`
nits:
- move more `NullDisplayText` bits into proper slots (just above `Order`)
- add doc comments for `ComputeNullDisplayText()`
- add more assertions in tests using `ModelStateDictionary.HasReachedMaxErrors`
- remove some trailing whitespace
- avoid `Assert.True()` & `Assert.False()`; split some assertions up
- `""` -> `string.Empty` in affected test classes
- rename "DefaultEditorTemplatesTest~~s~~" class and file to follow guidelines
- rename "ModelBindingTest~~s~~" class and file to follow guidelines
FYI #1888 covers a predictable (or even just stable) order in the UI
