Task manager is a tool developed for Salesforce which eases project development management. Users can create records for each task they are performing and inside those tasks, records for the metadatas they are modifying/creating. For instance: If an user modifies apex class: AccountUtility for task "Task - Account management": That user (Salesforce developer) would create a Task__c record named Task - Account management and inside of it, create an TaskItem__c named AccountUtility with the TaskItemType "ApexClass" By doing so, system will create automatically the Package.xml needed to retrieve and deploy
TaskManager also provides support for test classes: user can create a record of ApexElement__c and TestClass__c. In the example above, it would be for instance: a record for ApexElement__c --> AccountUtility a record for TestClass__c --> AccountUtiityTest
By relating both records with junction object "TestClassForApexElement__c" System will search all records of TaskItem__c which name is the same of the ApexElement__c and note down in a field in Task__c the list of methods that would be needed to run in the target production organization to deploy the elements listed in TaskItem__c