Specflow table column binding prevent Nulls - bdd

Question

Given the following code:
public class Bob {
public string Name { get; set; }
public int Age { get; set; }
public decimal Height { get; set; }
}
Feature: Bob checker
Scenario: Check Bob
Given I have the following Bob
| Name | Age | Hieght |
| Robert | 63 | 1.87 |
When . . . .
Then . . . .
[Given(#"I have the following Bob")]
public void IHaveTheFollowingBob(Table table) {
var bob = table.CreateInstance<Bob>();
}
You'l notice the word 'Height' is not spelt correctly in the table. The CreateInstance method will still work but the 'Height' on the Bob object will be 0 or for reference type, null.
Is there a way to make SpecFlow fail if the column doesn't bind to the Type provided. Thanks

Answer 1

There is no such thing as throwing error if there is a column that does not match any of the class properties.
However there is a work-arround. You may implement a method to check if there is an "invalid" column to prevent typos:
[Given("I have the following Bob")]
public void TestMethod1(Table table)
{
AssertAllTableColumnsMatch<Bob>(table);
var bob = table.CreateInstance<Bob>();
}
public void AssertAllTableColumnsMatch<T>(Table table)
{
foreach (var header in table.Header)
{
bool columnHeaderMatches = HasProperty(typeof(T), header);
Assert.IsTrue(columnHeaderMatches,
string.Format("The column header [{0}] does not match any property of the type [{1}]",
header, typeof(T).Name));
}
}
private bool HasProperty(Type obj, string propertyName)
{
return obj.GetProperty(propertyName) != null;
}
The following error will be thrown:
-> error: Assert.IsTrue failed. The column header [Hieght] does not match any property of the type [Bob]
The method simply iterates all the columns and checks if the provided type has such property.

Answer 2

I should RTFM. table.CompareToInstance(bob); Will fail if the Property is not there or is not populated the correctly. If you use this in conjuction with table.CreateInstance you will get failures where there are nulls. Leaving Q&A here just in case anyone else has brain fail.
SpecFlow Assist Helper, CompareToInstance
If you have have complex types you can represent them in the table and use IValueRetrieverand IValueComparer extensions
For example consider the following micky mouse code:
public class Bob {
public string Name { get; set; }
public int Age { get; set; }
public decimal Height { get; set; }
}
public class BobModel {
public string Name { get; set; }
public int Age { get; set; }
public decimal Height { get; set; }
}
Feature: Bob checker
Scenario: Check Bob
Given I have the following Bob
| Name | Age | Hieght |
| Robert | 63 | 1.87 |
When I map this to the model
Then Bob the model looks like this
| Name | Age | Height |
| Robert | 63 | 1.87 |
[Given(#"I have the following Bob")]
public void IHaveTheFollowingBob(Table table) {
var bob = table.CreateInstance<Bob>();
}
[When(#"I map this to the model")]
public void IMapThisToTheModel() {
sut = production.Map(bob);
}
[Then(#"Bob the model looks like this") {
public void BobTheModelLooksLikeThis(Table table) {
table.CompareToInstance<BobModel>(sut);
}
In this instance if there was a typo in the second table it would fail saying it can't find the property. If there is a typo in the first table then this will still be null but the assertion will fail. No false positives