public class akProcessInboundStageM1 implements Messaging.InboundEmailHandler {
    public Messaging.InboundEmailResult handleInboundEmail(Messaging.inboundEmail email, Messaging.InboundEnvelope env){
                
        // Create an InboundEmailResult object for returning the result of the Apex Email Service
        Messaging.InboundEmailResult result = new Messaging.InboundEmailResult();        
        
        String [] emailToList = email.toAddresses;
        String newSalesStage;
        String newMarketingStage;
        
        newSalesStage = null;
        newMarketingStage = 'Stage 1';
        
        akUpdateToutAppStages c = new akUpdateToutAppStages();
        c.processStage(newSalesStage, newMarketingStage, emailToList);
        
        return result;
    }
}

public class akUpdateToutAppStages {
    
    public void processStage(String newSalesStage, String newMarketingStage, String[] emailToList){
                
        String currentSalesStage;
        String currentMarketingStage;
        
        // Select a list of contacts from the database whose email address matches
        List<Contact> EmailMatches = [SELECT Id, Name, ToutApp_Marketing_Stage__c, ToutApp_Sales_Stage__c FROM Contact WHERE Email = :emailToList];
        
        if (EmailMatches.size() > 0){
            // Loop through the list of contacts and update the MarketingCampaign field
            for(Contact c : EmailMatches){
                currentSalesStage = c.ToutApp_Sales_Stage__c; // Stores the current value of Sales Campaign
                currentMarketingStage = c.ToutApp_Marketing_Stage__c; // Stores the current value of Marketing Campaign
                if (newSalesStage == null) newSalesStage = currentSalesStage; // If the new value is blank then it keeps the old value
                if (newMarketingStage == null) newMarketingStage = currentMarketingStage; // If the new value is blank then it keeps the old value
                c.ToutApp_Sales_Stage__c = newSalesStage;
                c.ToutApp_Marketing_Stage__c = newMarketingStage;
                System.debug('Updated Marketing Campaign Field for ' + c.Name );
            }
            
            // Update the Contact record
            update EmailMatches;
         }      
        
        else {
            System.debug('No Matching Email Addresses Found');
        }

    }
}

@isTest
private class akProcessInboundTest {
    static testMethod void akProcessInboundTest() {
        // create a new email and envelope object
         
        Messaging.InboundEmail email = new Messaging.InboundEmail();
        Messaging.InboundEnvelope env = new Messaging.InboundEnvelope();
       
        // setup the data for the email
        
        String[] TestToList = new String[] {'me@email1.com','you@email2.com'};
        email.toAddresses = TestToList;
        env.fromAddress = 'someaddress@email.com';
        email.subject = 'Congratulations on your recent funding';
                
        // call the class and test it with the data in the testMethod
        Test.startTest();
        akProcessInboundStageS1 s1 = new akProcessInboundStageS1();
        s1.handleInboundEmail(email, env);
      
        akProcessInboundStageS2 s2 = new akProcessInboundStageS2();
        s2.handleInboundEmail(email, env);

        akProcessInboundStageS3 s3 = new akProcessInboundStageS3();
        s3.handleInboundEmail(email, env);

        akProcessInboundStageS4 s4 = new akProcessInboundStageS4();
        s4.handleInboundEmail(email, env);

        akProcessInboundStageS5 s5 = new akProcessInboundStageS5();
        s5.handleInboundEmail(email, env);

        akProcessInboundStageS6 s6 = new akProcessInboundStageS6();
        s6.handleInboundEmail(email, env);
        
        akProcessInboundStageM1 m1 = new akProcessInboundStageM1();
        m1.handleInboundEmail(email, env);

        akProcessInboundStageM2 m2 = new akProcessInboundStageM2();
        m2.handleInboundEmail(email, env);
        
        akProcessInboundStageM3 m3 = new akProcessInboundStageM3();
        m3.handleInboundEmail(email, env);

        akProcessInboundStageM4 m4 = new akProcessInboundStageM4();
        m4.handleInboundEmail(email, env);
        
        akProcessInboundStageM5 m5 = new akProcessInboundStageM5();
        m5.handleInboundEmail(email, env);
        
        akProcessInboundStageM6 m6 = new akProcessInboundStageM6();
        m6.handleInboundEmail(email, env);
        
        akProcessInboundStageM7 m7 = new akProcessInboundStageM7();
        m7.handleInboundEmail(email, env);
        
        akProcessInboundStageM8 m8 = new akProcessInboundStageM8();
        m8.handleInboundEmail(email, env);
        
        akProcessInboundStageM9 m9 = new akProcessInboundStageM9();
        m9.handleInboundEmail(email, env);
        
        akProcessInboundStageM10 m10 = new akProcessInboundStageM10();
        m10.handleInboundEmail(email, env);

        akProcessInboundStageR1 r1 = new akProcessInboundStageR1();
        r1.handleInboundEmail(email, env);

        
        Test.stopTest();
    }
    static testMethod void UpdateToutAppTest() {     
    
        List<String> emailToList = new List<String>{'test1@email.com','test2@email.com'};
        String newSalesStage;
        String newMarketingStage;
        
        newSalesStage = 'Stage 1';
        newMarketingStage = null;
        
        Contact newContact = new Contact(LastName='TestContact', FirstName='TestContactF', Email='test1@email.com', MailingCountryCode='US', Funnel_Stage__c='Lead');
        insert newContact;
        
        Test.startTest();
        akUpdateToutAppStages c = new akUpdateToutAppStages();
        c.processStage(newSalesStage, newMarketingStage, emailToList);        
        Test.stopTest();
    }
}