Automatically create simple mocks for protocols in Swift

automock.stencil

{% for type in types.protocols.implementing.AutoMockable %}
{% if not type.name == "AutoMockable" %}
class {{ type.name }}Mock: {{ type.name }} {
    {% for method in type.allMethods %}
    //MARK: - {{ method.shortName }}
    
    var {{ method.shortName }}Called = false
    {% if not method.parameters.count == 0 %}var {{ method.shortName }}RecievedArguments: ({% for param in method.parameters %}{{ param.name }}: {{ param.typeName }}{% if not forloop.last %}, {% endif %}{% endfor %})?
    {% endif %}{% if not method.returnTypeName.isVoid %}
    var {{ method.shortName }}ReturnValue: {{ method.returnTypeName }}!
    {% endif %}
    func {{ method.shortName }}({% for param in method.parameters %}{{ param.argumentLabel }}{% if not param.argumentLabel == param.name %} {{ param.name }}{% endif %}: {{ param.typeName }}{% if not forloop.last %}, {% endif %}{% endfor %}){% if not method.returnTypeName.isVoid %} -> {{ method.returnTypeName }}{% endif %} {
        {{ method.shortName }}Called = true
        {{ method.shortName }}RecievedArguments = ({% for param in method.parameters %}{{ param.name }}: {{ param.name }}{% if not forloop.last%}, {% endif %}{% endfor %}){% if not method.returnTypeName.isVoid %}
        
        return {{ method.shortName }}ReturnValue{% endif %}
    }
    
    {% endfor %}
}
{% endif %}
{% endfor %}

DataService.swift

import Foundation

/// Protocols confoming to this protocol will have a mock generated for them.
protocol AutoMockable {}

protocol DataServiceProtocol: AutoMockable {
    
    func fullUrl(forPath path: String)-> String
    func fetchResource(fromURL url: URL, onComplete: (Result)-> Void)
    
}

class DataService: DataServiceProtocol {
    
    func fullUrl(forPath path: String)-> String {
        
        //Real implementation
        //Will get replaced in the generated file
        
        return baseURL + path
    }
    
    func fetchResource(fromURL url: URL, onComplete: (Result)-> Void) {
        
        //Real implementation
        //Will get replaced in the generated file
        
    }
    
}

DataServiceMock.swift

// Generated using Sourcery 0.5.0 — https://github.com/krzysztofzablocki/Sourcery
// DO NOT EDIT






class DataServiceProtocolMock: DataServiceProtocol {
    
    //MARK: - fullUrl
    
    var fullUrlCalled = false
    var fullUrlRecievedArguments: (path: String)?
    
    var fullUrlReturnValue: String!
    
    func fullUrl(forPath path: String) -> String {
        fullUrlCalled = true
        fullUrlRecievedArguments = (path: path)
        
        return fullUrlReturnValue
    }
    
    
    //MARK: - fetchResource
    
    var fetchResourceCalled = false
    var fetchResourceRecievedArguments: (url: URL, onComplete: (Result)-> Void)?
    
    func fetchResource(fromURL url: URL, onComplete: (Result)-> Void) {
        fetchResourceCalled = true
        fetchResourceRecievedArguments = (url: url, onComplete: onComplete)
    }
    
    
}

description.md

Automatically generates a mock class implementing a specific protocol. For each protocol method, the mock will provide a methodNameCalled boolean. Files:

• DataService.swift - sample file
• lens.stencil - sourcery template
• DataServiceMock.swift - sample mock generated

You will need sourcery template for this to work.

Issues and limitations:

• Function parameters that are @escaping closures will produce a compiler error when declaring the recievedArguments tuple, because functions tuples are implicitly escaping, so there's no need for @escaping. To fix this, simply remove the @escaping from the declaration.
• For now, only protocol methods will be mocked. Variables are coming!
• Overloaded methods will produce compiler warnings since they have the same name.

Suggestions and improvements are welcome!

Inspired by Filip Zawada.