Why doesn't this class have 100% test coverage, if it only has one function, and I test that function?

Question

I'm confused how Salesforce calculates test coverage. I've been struggling to get my app up to the 75% threshold. I have a number of files where I assume coverage should be 100%, but Salesforce says I only have 51% coverage. For instance, here is a class that only has one function, and I test this function, so I would expect to get 100% coverage. But Salesforce says I only have 51% coverage on this file. What do I need to do to get this coverage higher?

I'll shorten this file slightly to make it readable, but I have a class that has just one static function, and this is what it looks like:

/*
 *
 * type_of_permission should be either "select" or "insert" or "update", so you would call
 * using one of these 3 arguments:
 *
 *  SameDayPermissionModel.checkPermissions('select')
 *
 *  SameDayPermissionModel.checkPermissions('insert')
 *
 *  SameDayPermissionModel.checkPermissions('update')
 *
 */
public static boolean checkPermissions(String type_of_permission) {

    boolean permitted = true;


    if ( type_of_permission != 'select'  && type_of_permission != 'insert'  && type_of_permission != 'update'  && type_of_permission != 'delete' ) {
        return false; 
    }



    if (type_of_permission == 'select') {

        if (!Schema.sObjectType.FastCash__SameDaySummaryForProfileImport__c.isAccessible()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDaySession__c.isAccessible()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__Search__c.isAccessible()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayNote__c.isAccessible()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayImport__c.isAccessible()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDay_Flash_Message__c.isAccessible()) {
            permitted = false;
        }

    }



    if (type_of_permission == 'insert') {

        if (!Schema.sObjectType.FastCash__SameDaySummaryForProfileImport__c.isCreateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDaySession__c.isCreateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__Search__c.isCreateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayNote__c.isCreateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayImport__c.isCreateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDay_Flash_Message__c.isCreateable()) {
            permitted = false;
        }
    }




    if (type_of_permission == 'update') {

        if (!Schema.sObjectType.FastCash__SameDaySummaryForProfileImport__c.isUpdateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDaySession__c.isUpdateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__Search__c.isUpdateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayNote__c.isUpdateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayImport__c.isUpdateable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDay_Flash_Message__c.isUpdateable()) {
            permitted = false;
        }
    }




    /*
     * 2017-08-09 -- I'm fairly sure that the only place we delete anything is in the unit tests,
     * where we create a test object, insert it, then delete it.
     *
     *
     */
    if (type_of_permission == 'delete') {

        if (!Schema.sObjectType.FastCash__SameDaySummaryForProfileImport__c.isDeletable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDaySession__c.isDeletable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__Search__c.isDeletable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayNote__c.isDeletable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDayImport__c.isDeletable()) {
            permitted = false;
        }

        if (!Schema.sObjectType.FastCash__SameDay_Flash_Message__c.isDeletable()) {
            permitted = false;
        }

    }

    return permitted;
}

And then I have these tests in place:

@isTest
static  void testCheckPermissionsUpdate(){

    // Perform test logic
    Test.startTest();

    boolean wasThisAllowed = SameDayPermissionModel.checkPermissions('update');

    Test.stopTest();

    System.assertEquals(true, wasThisAllowed, 'SameDayPermissionModel.checkPermissions(select) should return true -- if this is not true, then that means the admin who is installing this app has restricted the permissions to a point that the SameDay Search Tool will not run correctly, in which case it is appropriate that this test should fail.');

}


@isTest
static  void testCheckPermissionsIncorrect(){

    // Perform test logic
    Test.startTest();

    boolean wasThisAllowed = SameDayPermissionModel.checkPermissions('an incorrect string');

    Test.stopTest();

    System.assertEquals(false, wasThisAllowed, 'SameDayPermissionModel.checkPermissions() takes either select, insert, or update as a string and then tests either isAccessbile() or isCreateable() or isUpdateable(). If some other string, besides those 3, is given as an argument, then the return value is false.');

}

I have tests for all four allowed inputs, but I cut those for the sake of brevity.

All tests are passing.

Can anyone tell me why Salesforce does not consider this 100% coverage? Why is this only 51% coverage? What else do I need to do to get 100%?

[ [ UPDATE ] ]

Robert Watson pointed me to the coverage report. I now see that Salesforce does not feel that these lines are tested:

        if (!Schema.sObjectType.FastCash__SameDaySummaryForProfileImport__c.isAccessible()) {
            permitted = false;
        }

But as near as I can see, these lines are tested, they are testing to see if a custom object has a permission.

Answer 1

It's no surprise at all you don't get 100% coverage. You need to test each code path. Here, you have variations on:

if (input == 'select')
{
    // Code Block 1
}
if (input == 'insert')
{
    // Code Block 2
}
if (input == 'update')
{
    // Code Block 3
}
if (input == 'delete')
{
    // Code Block 4
}

But you only check Code Block 3. You need to create a separate unit test each where you pass select, insert, and delete.