diff --color-moved: add perf tests

Add some tests so we can monitor changes to the performance of the
move detection code. The tests record the performance --color-moved
and --color-moved-ws=allow-indentation-change for a large diff and a
sequence of smaller diffs. The range of commits used for the large
diff can be customized by exporting TEST_REV_A and TEST_REV_B when
running the test.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/perf/p4002-diff-color-moved.sh b/t/perf/p4002-diff-color-moved.sh
new file mode 100755 (executable)
index 0000000..ab2af93
--- /dev/null
+++ b/t/perf/p4002-diff-color-moved.sh
@@ -0,0 +1,57 @@
+#!/bin/sh
+
+test_description='Tests diff --color-moved performance'
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# The endpoints of the diff can be customized by setting TEST_REV_A
+# and TEST_REV_B in the environment when running this test.
+
+rev="${TEST_REV_A:-v2.28.0}"
+if ! rev_a="$(git rev-parse --quiet --verify "$rev")"
+then
+       skip_all="skipping because '$rev' was not found. \
+                 Use TEST_REV_A and TEST_REV_B to set the revs to use"
+       test_done
+fi
+rev="${TEST_REV_B:-v2.29.0}"
+if ! rev_b="$(git rev-parse --quiet --verify "$rev")"
+then
+       skip_all="skipping because '$rev' was not found. \
+                 Use TEST_REV_A and TEST_REV_B to set the revs to use"
+       test_done
+fi
+
+GIT_PAGER_IN_USE=1
+test_export GIT_PAGER_IN_USE rev_a rev_b
+
+test_perf 'diff --no-color-moved --no-color-moved-ws large change' '
+       git diff --no-color-moved --no-color-moved-ws $rev_a $rev_b
+'
+
+test_perf 'diff --color-moved --no-color-moved-ws large change' '
+       git diff --color-moved=zebra --no-color-moved-ws $rev_a $rev_b
+'
+
+test_perf 'diff --color-moved-ws=allow-indentation-change large change' '
+       git diff --color-moved=zebra --color-moved-ws=allow-indentation-change \
+               $rev_a $rev_b
+'
+
+test_perf 'log --no-color-moved --no-color-moved-ws' '
+       git log --no-color-moved --no-color-moved-ws --no-merges --patch \
+               -n1000 $rev_b
+'
+
+test_perf 'log --color-moved --no-color-moved-ws' '
+       git log --color-moved=zebra --no-color-moved-ws --no-merges --patch \
+               -n1000 $rev_b
+'
+
+test_perf 'log --color-moved-ws=allow-indentation-change' '
+       git log --color-moved=zebra --color-moved-ws=allow-indentation-change \
+               --no-merges --patch -n1000 $rev_b
+'
+
+test_done