what if the master branch got updated in between code example

Example 1: git update branch from master

git checkout test-branch 	//Checkout the branch you want to update
git merge master			//Merge all code from master to test-branch

// When your are done with test-branch you can merge all code into master branch
git checkout master 		// Make sure you are on master branch
git merge test-branch

Example 2: git how to update branch from master

git fetch
git rebase origin/master