add c5 in master branch
add c4 in test branch
master branch modify c2
master branch modify c2 again
test branch modify c1
test branch modify c1 again
first change by master
first change by master again
second change by master
first change by b1
second change by b1
reset c1 by master
b1 add
master add
b1 add again
master add again
master fix conflict
b1 modify c2
master modify c1
Merge branch 'b1'