Feature: Enumerated values
@enum
Scenario: Enumerated values
Given a YAML schema:
```
enum:
- red
- amber
- green
```
Then it should accept:
```
red
```
And it should accept:
```
green
```
But it should NOT accept:
```
blue
```
@enum
Scenario: enum without a type
Given a YAML schema:
```
enum:
- red
- amber
- green
- null
- 42
```
Then it should accept:
```
red
```
And it should accept:
```
null
```
And it should accept:
```
42
```
But it should NOT accept:
```
0
```
@enum
Scenario: enum of other types
Given a YAML schema:
```
type: object
properties:
version:
type: integer
enum: [1]
```
Then it should accept:
```
version: 1
```
But it should NOT accept:
```
version: 2
```