Add several testcases for --dirstat and friends

Currently, t4013 is the only selftest that exercises the --dirstat machinery,
but it only does a superficial verification of --dirstat's output.

This patch adds a new selftest - t4047-diff-dirstat.sh - which prepares a
commit containing:
 - unchanged files, changed files and files with rearranged lines
 - copied files, moved files, and unmoved files

It then verifies the correct dirstat output for that commit in the following
dirstat modes:
 - --dirstat
 - -X
 - --dirstat=0
 - -X0
 - --cumulative
 - --dirstat-by-file
 - (plus combinations of the above)

Each of the above tests are also run with:
 - no rename detection
 - rename detection (-M)
 - expensive copy detection (-C -C)
Improved-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NJohan Herland <johan@herland.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t4047-diff-dirstat.sh

+#!/bin/sh
+
+test_description='diff --dirstat tests'
+. ./test-lib.sh
+
+# set up two commits where the second commit has these files
+# (10 lines in each file):
+#
+#   unchanged/text           (unchanged from 1st commit)
+#   changed/text             (changed 1st line)
+#   rearranged/text          (swapped 1st and 2nd line)
+#   dst/copy/unchanged/text  (copied from src/copy/unchanged/text, unchanged)
+#   dst/copy/changed/text    (copied from src/copy/changed/text, changed)
+#   dst/copy/rearranged/text (copied from src/copy/rearranged/text, rearranged)
+#   dst/move/unchanged/text  (moved from src/move/unchanged/text, unchanged)
+#   dst/move/changed/text    (moved from src/move/changed/text, changed)
+#   dst/move/rearranged/text (moved from src/move/rearranged/text, rearranged)
+
+test_expect_success 'setup' '
+	mkdir unchanged &&
+	mkdir changed &&
+	mkdir rearranged &&
+	mkdir src &&
+	mkdir src/copy &&
+	mkdir src/copy/unchanged &&
+	mkdir src/copy/changed &&
+	mkdir src/copy/rearranged &&
+	mkdir src/move &&
+	mkdir src/move/unchanged &&
+	mkdir src/move/changed &&
+	mkdir src/move/rearranged &&
+	cat <<EOF >unchanged/text &&
+unchanged       line #0
+unchanged       line #1
+unchanged       line #2
+unchanged       line #3
+unchanged       line #4
+unchanged       line #5
+unchanged       line #6
+unchanged       line #7
+unchanged       line #8
+unchanged       line #9
+EOF
+	cat <<EOF >changed/text &&
+changed         line #0
+changed         line #1
+changed         line #2
+changed         line #3
+changed         line #4
+changed         line #5
+changed         line #6
+changed         line #7
+changed         line #8
+changed         line #9
+EOF
+	cat <<EOF >rearranged/text &&
+rearranged      line #0
+rearranged      line #1
+rearranged      line #2
+rearranged      line #3
+rearranged      line #4
+rearranged      line #5
+rearranged      line #6
+rearranged      line #7
+rearranged      line #8
+rearranged      line #9
+EOF
+	cat <<EOF >src/copy/unchanged/text &&
+copy  unchanged line #0
+copy  unchanged line #1
+copy  unchanged line #2
+copy  unchanged line #3
+copy  unchanged line #4
+copy  unchanged line #5
+copy  unchanged line #6
+copy  unchanged line #7
+copy  unchanged line #8
+copy  unchanged line #9
+EOF
+	cat <<EOF >src/copy/changed/text &&
+copy    changed line #0
+copy    changed line #1
+copy    changed line #2
+copy    changed line #3
+copy    changed line #4
+copy    changed line #5
+copy    changed line #6
+copy    changed line #7
+copy    changed line #8
+copy    changed line #9
+EOF
+	cat <<EOF >src/copy/rearranged/text &&
+copy rearranged line #0
+copy rearranged line #1
+copy rearranged line #2
+copy rearranged line #3
+copy rearranged line #4
+copy rearranged line #5
+copy rearranged line #6
+copy rearranged line #7
+copy rearranged line #8
+copy rearranged line #9
+EOF
+	cat <<EOF >src/move/unchanged/text &&
+move  unchanged line #0
+move  unchanged line #1
+move  unchanged line #2
+move  unchanged line #3
+move  unchanged line #4
+move  unchanged line #5
+move  unchanged line #6
+move  unchanged line #7
+move  unchanged line #8
+move  unchanged line #9
+EOF
+	cat <<EOF >src/move/changed/text &&
+move    changed line #0
+move    changed line #1
+move    changed line #2
+move    changed line #3
+move    changed line #4
+move    changed line #5
+move    changed line #6
+move    changed line #7
+move    changed line #8
+move    changed line #9
+EOF
+	cat <<EOF >src/move/rearranged/text &&
+move rearranged line #0
+move rearranged line #1
+move rearranged line #2
+move rearranged line #3
+move rearranged line #4
+move rearranged line #5
+move rearranged line #6
+move rearranged line #7
+move rearranged line #8
+move rearranged line #9
+EOF
+	git add . &&
+	git commit -m "initial" &&
+	mkdir dst &&
+	mkdir dst/copy &&
+	mkdir dst/copy/unchanged &&
+	mkdir dst/copy/changed &&
+	mkdir dst/copy/rearranged &&
+	mkdir dst/move &&
+	mkdir dst/move/unchanged &&
+	mkdir dst/move/changed &&
+	mkdir dst/move/rearranged &&
+	cat <<EOF >changed/text &&
+CHANGED XXXXXXX line #0
+changed         line #1
+changed         line #2
+changed         line #3
+changed         line #4
+changed         line #5
+changed         line #6
+changed         line #7
+changed         line #8
+changed         line #9
+EOF
+	cat <<EOF >rearranged/text &&
+rearranged      line #1
+rearranged      line #0
+rearranged      line #2
+rearranged      line #3
+rearranged      line #4
+rearranged      line #5
+rearranged      line #6
+rearranged      line #7
+rearranged      line #8
+rearranged      line #9
+EOF
+	cat <<EOF >dst/copy/unchanged/text &&
+copy  unchanged line #0
+copy  unchanged line #1
+copy  unchanged line #2
+copy  unchanged line #3
+copy  unchanged line #4
+copy  unchanged line #5
+copy  unchanged line #6
+copy  unchanged line #7
+copy  unchanged line #8
+copy  unchanged line #9
+EOF
+	cat <<EOF >dst/copy/changed/text &&
+copy XXXCHANGED line #0
+copy    changed line #1
+copy    changed line #2
+copy    changed line #3
+copy    changed line #4
+copy    changed line #5
+copy    changed line #6
+copy    changed line #7
+copy    changed line #8
+copy    changed line #9
+EOF
+	cat <<EOF >dst/copy/rearranged/text &&
+copy rearranged line #1
+copy rearranged line #0
+copy rearranged line #2
+copy rearranged line #3
+copy rearranged line #4
+copy rearranged line #5
+copy rearranged line #6
+copy rearranged line #7
+copy rearranged line #8
+copy rearranged line #9
+EOF
+	cat <<EOF >dst/move/unchanged/text &&
+move  unchanged line #0
+move  unchanged line #1
+move  unchanged line #2
+move  unchanged line #3
+move  unchanged line #4
+move  unchanged line #5
+move  unchanged line #6
+move  unchanged line #7
+move  unchanged line #8
+move  unchanged line #9
+EOF
+	cat <<EOF >dst/move/changed/text &&
+move XXXCHANGED line #0
+move    changed line #1
+move    changed line #2
+move    changed line #3
+move    changed line #4
+move    changed line #5
+move    changed line #6
+move    changed line #7
+move    changed line #8
+move    changed line #9
+EOF
+	cat <<EOF >dst/move/rearranged/text &&
+move rearranged line #1
+move rearranged line #0
+move rearranged line #2
+move rearranged line #3
+move rearranged line #4
+move rearranged line #5
+move rearranged line #6
+move rearranged line #7
+move rearranged line #8
+move rearranged line #9
+EOF
+	git add . &&
+	git rm -r src/move/unchanged &&
+	git rm -r src/move/changed &&
+	git rm -r src/move/rearranged &&
+	git commit -m "changes"
+'
+
+cat <<EOF >expect_diff_stat
+ changed/text             |    2 +-
+ dst/copy/changed/text    |   10 ++++++++++
+ dst/copy/rearranged/text |   10 ++++++++++
+ dst/copy/unchanged/text  |   10 ++++++++++
+ dst/move/changed/text    |   10 ++++++++++
+ dst/move/rearranged/text |   10 ++++++++++
+ dst/move/unchanged/text  |   10 ++++++++++
+ rearranged/text          |    2 +-
+ src/move/changed/text    |   10 ----------
+ src/move/rearranged/text |   10 ----------
+ src/move/unchanged/text  |   10 ----------
+ 11 files changed, 62 insertions(+), 32 deletions(-)
+EOF
+
+cat <<EOF >expect_diff_stat_M
+ changed/text                      |    2 +-
+ dst/copy/changed/text             |   10 ++++++++++
+ dst/copy/rearranged/text          |   10 ++++++++++
+ dst/copy/unchanged/text           |   10 ++++++++++
+ {src => dst}/move/changed/text    |    2 +-
+ {src => dst}/move/rearranged/text |    2 +-
+ {src => dst}/move/unchanged/text  |    0
+ rearranged/text                   |    2 +-
+ 8 files changed, 34 insertions(+), 4 deletions(-)
+EOF
+
+cat <<EOF >expect_diff_stat_CC
+ changed/text                      |    2 +-
+ {src => dst}/copy/changed/text    |    2 +-
+ {src => dst}/copy/rearranged/text |    2 +-
+ {src => dst}/copy/unchanged/text  |    0
+ {src => dst}/move/changed/text    |    2 +-
+ {src => dst}/move/rearranged/text |    2 +-
+ {src => dst}/move/unchanged/text  |    0
+ rearranged/text                   |    2 +-
+ 8 files changed, 6 insertions(+), 6 deletions(-)
+EOF
+
+test_expect_success 'sanity check setup (--stat)' '
+	git diff --stat HEAD^..HEAD >actual_diff_stat &&
+	test_cmp expect_diff_stat actual_diff_stat &&
+	git diff --stat -M HEAD^..HEAD >actual_diff_stat_M &&
+	test_cmp expect_diff_stat_M actual_diff_stat_M &&
+	git diff --stat -C -C HEAD^..HEAD >actual_diff_stat_CC &&
+	test_cmp expect_diff_stat_CC actual_diff_stat_CC
+'
+
+# changed/text and rearranged/text falls below default 3% threshold
+cat <<EOF >expect_diff_dirstat
+  10.8% dst/copy/changed/
+  10.8% dst/copy/rearranged/
+  10.8% dst/copy/unchanged/
+  10.8% dst/move/changed/
+  10.8% dst/move/rearranged/
+  10.8% dst/move/unchanged/
+  10.8% src/move/changed/
+  10.8% src/move/rearranged/
+  10.8% src/move/unchanged/
+EOF
+
+# rearranged/text falls below default 3% threshold
+cat <<EOF >expect_diff_dirstat_M
+   5.8% changed/
+  29.3% dst/copy/changed/
+  29.3% dst/copy/rearranged/
+  29.3% dst/copy/unchanged/
+   5.8% dst/move/changed/
+EOF
+
+# rearranged/text falls below default 3% threshold
+cat <<EOF >expect_diff_dirstat_CC
+  32.6% changed/
+  32.6% dst/copy/changed/
+  32.6% dst/move/changed/
+EOF
+
+test_expect_success 'various ways to misspell --dirstat' '
+	test_must_fail git show --dirstat10 &&
+	test_must_fail git show -X=20
+'
+
+test_expect_success 'vanilla --dirstat' '
+	git diff --dirstat HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_expect_success 'vanilla -X' '
+	git diff -X HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff -X -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff -X -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+# rearranged/text falls below 0% threshold (1 / (240 * 9 + 48 + 1) ~= 0.045 %)
+cat <<EOF >expect_diff_dirstat
+   2.1% changed/
+  10.8% dst/copy/changed/
+  10.8% dst/copy/rearranged/
+  10.8% dst/copy/unchanged/
+  10.8% dst/move/changed/
+  10.8% dst/move/rearranged/
+  10.8% dst/move/unchanged/
+  10.8% src/move/changed/
+  10.8% src/move/rearranged/
+  10.8% src/move/unchanged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_M
+   5.8% changed/
+  29.3% dst/copy/changed/
+  29.3% dst/copy/rearranged/
+  29.3% dst/copy/unchanged/
+   5.8% dst/move/changed/
+   0.1% dst/move/rearranged/
+   0.1% rearranged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_CC
+  32.6% changed/
+  32.6% dst/copy/changed/
+   0.6% dst/copy/rearranged/
+  32.6% dst/move/changed/
+   0.6% dst/move/rearranged/
+   0.6% rearranged/
+EOF
+
+test_expect_success '--dirstat=0' '
+	git diff --dirstat=0 HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat=0 -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat=0 -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_expect_success '-X0' '
+	git diff -X0 HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff -X0 -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff -X0 -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+# rearranged/text falls below 0% threshold (1 / (240 * 9 + 48 + 1) ~= 0.045 %)
+cat <<EOF >expect_diff_dirstat
+   2.1% changed/
+  10.8% dst/copy/changed/
+  10.8% dst/copy/rearranged/
+  10.8% dst/copy/unchanged/
+  32.5% dst/copy/
+  10.8% dst/move/changed/
+  10.8% dst/move/rearranged/
+  10.8% dst/move/unchanged/
+  32.5% dst/move/
+  65.1% dst/
+  10.8% src/move/changed/
+  10.8% src/move/rearranged/
+  10.8% src/move/unchanged/
+  32.5% src/move/
+EOF
+
+cat <<EOF >expect_diff_dirstat_M
+   5.8% changed/
+  29.3% dst/copy/changed/
+  29.3% dst/copy/rearranged/
+  29.3% dst/copy/unchanged/
+  88.0% dst/copy/
+   5.8% dst/move/changed/
+   0.1% dst/move/rearranged/
+   5.9% dst/move/
+  94.0% dst/
+   0.1% rearranged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_CC
+  32.6% changed/
+  32.6% dst/copy/changed/
+   0.6% dst/copy/rearranged/
+  33.3% dst/copy/
+  32.6% dst/move/changed/
+   0.6% dst/move/rearranged/
+  33.3% dst/move/
+  66.6% dst/
+   0.6% rearranged/
+EOF
+
+test_expect_success '--dirstat=0 --cumulative' '
+	git diff --dirstat=0 --cumulative HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat=0 --cumulative -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat=0 --cumulative -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+cat <<EOF >expect_diff_dirstat
+   9.0% changed/
+   9.0% dst/copy/changed/
+   9.0% dst/copy/rearranged/
+   9.0% dst/copy/unchanged/
+   9.0% dst/move/changed/
+   9.0% dst/move/rearranged/
+   9.0% dst/move/unchanged/
+   9.0% rearranged/
+   9.0% src/move/changed/
+   9.0% src/move/rearranged/
+   9.0% src/move/unchanged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_M
+  14.2% changed/
+  14.2% dst/copy/changed/
+  14.2% dst/copy/rearranged/
+  14.2% dst/copy/unchanged/
+  14.2% dst/move/changed/
+  14.2% dst/move/rearranged/
+  14.2% rearranged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_CC
+  16.6% changed/
+  16.6% dst/copy/changed/
+  16.6% dst/copy/rearranged/
+  16.6% dst/move/changed/
+  16.6% dst/move/rearranged/
+  16.6% rearranged/
+EOF
+
+test_expect_success '--dirstat-by-file' '
+	git diff --dirstat-by-file HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat-by-file -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat-by-file -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+cat <<EOF >expect_diff_dirstat
+  27.2% dst/copy/
+  27.2% dst/move/
+  27.2% src/move/
+EOF
+
+cat <<EOF >expect_diff_dirstat_M
+  14.2% changed/
+  14.2% dst/copy/changed/
+  14.2% dst/copy/rearranged/
+  14.2% dst/copy/unchanged/
+  14.2% dst/move/changed/
+  14.2% dst/move/rearranged/
+  14.2% rearranged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_CC
+  16.6% changed/
+  16.6% dst/copy/changed/
+  16.6% dst/copy/rearranged/
+  16.6% dst/move/changed/
+  16.6% dst/move/rearranged/
+  16.6% rearranged/
+EOF
+
+test_expect_success '--dirstat-by-file=10' '
+	git diff --dirstat-by-file=10 HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat-by-file=10 -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat-by-file=10 -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+cat <<EOF >expect_diff_dirstat
+   9.0% changed/
+   9.0% dst/copy/changed/
+   9.0% dst/copy/rearranged/
+   9.0% dst/copy/unchanged/
+  27.2% dst/copy/
+   9.0% dst/move/changed/
+   9.0% dst/move/rearranged/
+   9.0% dst/move/unchanged/
+  27.2% dst/move/
+  54.5% dst/
+   9.0% rearranged/
+   9.0% src/move/changed/
+   9.0% src/move/rearranged/
+   9.0% src/move/unchanged/
+  27.2% src/move/
+EOF
+
+cat <<EOF >expect_diff_dirstat_M
+  14.2% changed/
+  14.2% dst/copy/changed/
+  14.2% dst/copy/rearranged/
+  14.2% dst/copy/unchanged/
+  42.8% dst/copy/
+  14.2% dst/move/changed/
+  14.2% dst/move/rearranged/
+  28.5% dst/move/
+  71.4% dst/
+  14.2% rearranged/
+EOF
+
+cat <<EOF >expect_diff_dirstat_CC
+  16.6% changed/
+  16.6% dst/copy/changed/
+  16.6% dst/copy/rearranged/
+  33.3% dst/copy/
+  16.6% dst/move/changed/
+  16.6% dst/move/rearranged/
+  33.3% dst/move/
+  66.6% dst/
+  16.6% rearranged/
+EOF
+
+test_expect_success '--dirstat-by-file --cumulative' '
+	git diff --dirstat-by-file --cumulative HEAD^..HEAD >actual_diff_dirstat &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	git diff --dirstat-by-file --cumulative -M HEAD^..HEAD >actual_diff_dirstat_M &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	git diff --dirstat-by-file --cumulative -C -C HEAD^..HEAD >actual_diff_dirstat_CC &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
+'
+
+test_done