[GSoC][PATCH v3 3/4] t1422: refactor tests to be shareable

[Meet Soni <meetsoni3017@gmail.com>]

In preparation for adding tests for the `git refs exists` command,
refactor the existing t1422 test suite to make its logic shareable.

Move the core test logic from `t1422-show-ref-exists.sh` to
`show-ref-exists-tests.sh` file. Inside this script, replace hardcoded
calls to "git show-ref --exists" with the `$git_show_ref_exists`
variable.

The original `t1422-show-ref-exists.sh` script now becomes a simple
"driver". It is responsible for setting the default value of the
variable and then sourcing the test library.

This structure follows an established pattern for sharing tests and
prepares the test suite for the `refs exists` tests to be added in a
subsequent commit.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Meet Soni <meetsoni3017@gmail.com>
---
 t/show-ref-exists-tests.sh | 77 ++++++++++++++++++++++++++++++++++++++
 t/t1422-show-ref-exists.sh | 76 +------------------------------------
 2 files changed, 78 insertions(+), 75 deletions(-)
 create mode 100644 t/show-ref-exists-tests.sh
 mode change 100644 => 100755 t/t1422-show-ref-exists.sh

diff --git a/t/show-ref-exists-tests.sh b/t/show-ref-exists-tests.sh
new file mode 100644
index 0000000000..36e8e9df33
--- /dev/null
+++ b/t/show-ref-exists-tests.sh
@@ -0,0 +1,77 @@
+git_show_ref_exists=${git_show_ref_exists:-git show-ref --exists}
+
+test_expect_success setup '
+	test_commit --annotate A &&
+	git checkout -b side &&
+	test_commit --annotate B &&
+	git checkout main &&
+	test_commit C &&
+	git branch B A^0
+'
+
+test_expect_success '--exists with existing reference' '
+	${git_show_ref_exists} refs/heads/$GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+'
+
+test_expect_success '--exists with missing reference' '
+	test_expect_code 2 ${git_show_ref_exists} refs/heads/does-not-exist
+'
+
+test_expect_success '--exists does not use DWIM' '
+	test_expect_code 2 ${git_show_ref_exists} $GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME 2>err &&
+	grep "reference does not exist" err
+'
+
+test_expect_success '--exists with HEAD' '
+	${git_show_ref_exists} HEAD
+'
+
+test_expect_success '--exists with bad reference name' '
+	test_when_finished "git update-ref -d refs/heads/bad...name" &&
+	new_oid=$(git rev-parse HEAD) &&
+	test-tool ref-store main update-ref msg refs/heads/bad...name $new_oid $ZERO_OID REF_SKIP_REFNAME_VERIFICATION &&
+	${git_show_ref_exists} refs/heads/bad...name
+'
+
+test_expect_success '--exists with arbitrary symref' '
+	test_when_finished "git symbolic-ref -d refs/symref" &&
+	git symbolic-ref refs/symref refs/heads/$GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME &&
+	${git_show_ref_exists} refs/symref
+'
+
+test_expect_success '--exists with dangling symref' '
+	test_when_finished "git symbolic-ref -d refs/heads/dangling" &&
+	git symbolic-ref refs/heads/dangling refs/heads/does-not-exist &&
+	${git_show_ref_exists} refs/heads/dangling
+'
+
+test_expect_success '--exists with nonexistent object ID' '
+	test-tool ref-store main update-ref msg refs/heads/missing-oid $(test_oid 001) $ZERO_OID REF_SKIP_OID_VERIFICATION &&
+	${git_show_ref_exists} refs/heads/missing-oid
+'
+
+test_expect_success '--exists with non-commit object' '
+	tree_oid=$(git rev-parse HEAD^{tree}) &&
+	test-tool ref-store main update-ref msg refs/heads/tree ${tree_oid} $ZERO_OID REF_SKIP_OID_VERIFICATION &&
+	${git_show_ref_exists} refs/heads/tree
+'
+
+test_expect_success '--exists with directory fails with generic error' '
+	cat >expect <<-EOF &&
+	error: reference does not exist
+	EOF
+	test_expect_code 2 ${git_show_ref_exists} refs/heads 2>err &&
+	test_cmp expect err
+'
+
+test_expect_success '--exists with non-existent special ref' '
+	test_expect_code 2 ${git_show_ref_exists} FETCH_HEAD
+'
+
+test_expect_success '--exists with existing special ref' '
+	test_when_finished "rm .git/FETCH_HEAD" &&
+	git rev-parse HEAD >.git/FETCH_HEAD &&
+	${git_show_ref_exists} FETCH_HEAD
+'
+
+test_done
diff --git a/t/t1422-show-ref-exists.sh b/t/t1422-show-ref-exists.sh
old mode 100644
new mode 100755
index 0eccb2dce1..fdca3f16c8
--- a/t/t1422-show-ref-exists.sh
+++ b/t/t1422-show-ref-exists.sh
@@ -6,78 +6,4 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
-test_expect_success setup '
-	test_commit --annotate A &&
-	git checkout -b side &&
-	test_commit --annotate B &&
-	git checkout main &&
-	test_commit C &&
-	git branch B A^0
-'
-
-test_expect_success '--exists with existing reference' '
-	git show-ref --exists refs/heads/$GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
-'
-
-test_expect_success '--exists with missing reference' '
-	test_expect_code 2 git show-ref --exists refs/heads/does-not-exist
-'
-
-test_expect_success '--exists does not use DWIM' '
-	test_expect_code 2 git show-ref --exists $GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME 2>err &&
-	grep "reference does not exist" err
-'
-
-test_expect_success '--exists with HEAD' '
-	git show-ref --exists HEAD
-'
-
-test_expect_success '--exists with bad reference name' '
-	test_when_finished "git update-ref -d refs/heads/bad...name" &&
-	new_oid=$(git rev-parse HEAD) &&
-	test-tool ref-store main update-ref msg refs/heads/bad...name $new_oid $ZERO_OID REF_SKIP_REFNAME_VERIFICATION &&
-	git show-ref --exists refs/heads/bad...name
-'
-
-test_expect_success '--exists with arbitrary symref' '
-	test_when_finished "git symbolic-ref -d refs/symref" &&
-	git symbolic-ref refs/symref refs/heads/$GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME &&
-	git show-ref --exists refs/symref
-'
-
-test_expect_success '--exists with dangling symref' '
-	test_when_finished "git symbolic-ref -d refs/heads/dangling" &&
-	git symbolic-ref refs/heads/dangling refs/heads/does-not-exist &&
-	git show-ref --exists refs/heads/dangling
-'
-
-test_expect_success '--exists with nonexistent object ID' '
-	test-tool ref-store main update-ref msg refs/heads/missing-oid $(test_oid 001) $ZERO_OID REF_SKIP_OID_VERIFICATION &&
-	git show-ref --exists refs/heads/missing-oid
-'
-
-test_expect_success '--exists with non-commit object' '
-	tree_oid=$(git rev-parse HEAD^{tree}) &&
-	test-tool ref-store main update-ref msg refs/heads/tree ${tree_oid} $ZERO_OID REF_SKIP_OID_VERIFICATION &&
-	git show-ref --exists refs/heads/tree
-'
-
-test_expect_success '--exists with directory fails with generic error' '
-	cat >expect <<-EOF &&
-	error: reference does not exist
-	EOF
-	test_expect_code 2 git show-ref --exists refs/heads 2>err &&
-	test_cmp expect err
-'
-
-test_expect_success '--exists with non-existent special ref' '
-	test_expect_code 2 git show-ref --exists FETCH_HEAD
-'
-
-test_expect_success '--exists with existing special ref' '
-	test_when_finished "rm .git/FETCH_HEAD" &&
-	git rev-parse HEAD >.git/FETCH_HEAD &&
-	git show-ref --exists FETCH_HEAD
-'
-
-test_done
+. "$TEST_DIRECTORY"/show-ref-exists-tests.sh
-- 
2.34.1