t3507: introduce pristine-detach helper

All the tests in t3507 (cherry-pick with conflicts) begin with the
same checkout + read-tree + clean incantation to ensure a predictable
starting point.  Factor out a function for that so the interesting
part of the tests is easier to read.

The "update-index --refresh" and "diff-index --exit-code HEAD" are not
necessary as the point of this testsuite is not about testing
"read-tree --reset".

Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3507-cherry-pick-conflict.sh

@@ -11,6 +11,18 @@ test_description='test cherry-pick and revert with conflicts
 
 . ./test-lib.sh
 
+test_cmp_rev () {
+	git rev-parse --verify "$1" >expect.rev &&
+	git rev-parse --verify "$2" >actual.rev &&
+	test_cmp expect.rev actual.rev
+}
+
+pristine_detach () {
+	git checkout -f "$1^0" &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x
+}
+
 test_expect_success setup '
 
 	echo unrelated >unrelated &&
@@ -23,13 +35,7 @@ test_expect_success setup '
 '
 
 test_expect_success 'failed cherry-pick does not advance HEAD' '
-
-	git checkout -f initial^0 &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
-
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
+	pristine_detach initial &&
 
 	head=$(git rev-parse HEAD) &&
 	test_must_fail git cherry-pick picked &&
@@ -39,12 +45,7 @@ test_expect_success 'failed cherry-pick does not advance HEAD' '
 '
 
 test_expect_success 'advice from failed cherry-pick' "
-	git checkout -f initial^0 &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
-
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
+	pristine_detach initial &&
 
 	picked=\$(git rev-parse --short picked) &&
 	cat <<-EOF >expected &&
@@ -59,13 +60,7 @@ test_expect_success 'advice from failed cherry-pick' "
 "
 
 test_expect_success 'failed cherry-pick produces dirty index' '
-
-	git checkout -f initial^0 &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
-
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
+	pristine_detach initial &&
 
 	test_must_fail git cherry-pick picked &&
 
@@ -74,9 +69,7 @@ test_expect_success 'failed cherry-pick produces dirty index' '
 '
 
 test_expect_success 'failed cherry-pick registers participants in index' '
-
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
+	pristine_detach initial &&
 	{
 		git checkout base -- foo &&
 		git ls-files --stage foo &&
@@ -90,10 +83,7 @@ test_expect_success 'failed cherry-pick registers participants in index' '
 		2 s/ 0	/ 2	/
 		3 s/ 0	/ 3	/
 	" < stages > expected &&
-	git checkout -f initial^0 &&
-
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
+	git read-tree -u --reset HEAD &&
 
 	test_must_fail git cherry-pick picked &&
 	git ls-files --stage --unmerged > actual &&
@@ -102,10 +92,7 @@ test_expect_success 'failed cherry-pick registers participants in index' '
 '
 
 test_expect_success 'failed cherry-pick describes conflict in work tree' '
-
-	git checkout -f initial^0 &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
+	pristine_detach initial &&
 	cat <<-EOF > expected &&
 	<<<<<<< HEAD
 	a
@@ -114,21 +101,15 @@ test_expect_success 'failed cherry-pick describes conflict in work tree' '
 	>>>>>>> objid picked
 	EOF
 
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
-
 	test_must_fail git cherry-pick picked &&
 
 	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&
 	test_cmp expected actual
 '
 
 test_expect_success 'diff3 -m style' '
-
+	pristine_detach initial &&
 	git config merge.conflictstyle diff3 &&
-	git checkout -f initial^0 &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
 	cat <<-EOF > expected &&
 	<<<<<<< HEAD
 	a
@@ -139,20 +120,15 @@ test_expect_success 'diff3 -m style' '
 	>>>>>>> objid picked
 	EOF
 
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
-
 	test_must_fail git cherry-pick picked &&
 
 	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&
 	test_cmp expected actual
 '
 
 test_expect_success 'revert also handles conflicts sanely' '
-
 	git config --unset merge.conflictstyle &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
+	pristine_detach initial &&
 	cat <<-EOF > expected &&
 	<<<<<<< HEAD
 	a
@@ -173,10 +149,7 @@ test_expect_success 'revert also handles conflicts sanely' '
 		2 s/ 0	/ 2	/
 		3 s/ 0	/ 3	/
 	" < stages > expected-stages &&
-	git checkout -f initial^0 &&
-
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
+	git read-tree -u --reset HEAD &&
 
 	head=$(git rev-parse HEAD) &&
 	test_must_fail git revert picked &&
@@ -192,10 +165,8 @@ test_expect_success 'revert also handles conflicts sanely' '
 '
 
 test_expect_success 'revert conflict, diff3 -m style' '
+	pristine_detach initial &&
 	git config merge.conflictstyle diff3 &&
-	git checkout -f initial^0 &&
-	git read-tree -u --reset HEAD &&
-	git clean -d -f -f -q -x &&
 	cat <<-EOF > expected &&
 	<<<<<<< HEAD
 	a
@@ -206,9 +177,6 @@ test_expect_success 'revert conflict, diff3 -m style' '
 	>>>>>>> parent of objid picked
 	EOF
 
-	git update-index --refresh &&
-	git diff-index --exit-code HEAD &&
-
 	test_must_fail git revert picked &&
 
 	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&