Test the progress display

'progress.c' has seen a few fixes recently [1], and, unfortunately,
some of those fixes required further fixes [2].  It seems it's time to
have a few tests focusing on the subtleties of the progress display.

Add the 'test-tool progress' subcommand to help testing the progress
display, reading instructions from standard input and turning them
into calls to the display_progress() and display_throughput()
functions with the given parameters.

The progress display is, however, critically dependent on timing,
because it's only updated once every second or, if the toal is known
in advance, every 1%, and there is the throughput rate as well.  These
make the progress display far too undeterministic for testing as-is.
To address this, add a few testing-specific variables and functions to
'progress.c', allowing the the new test helper to:

  - Disable the triggered-every-second SIGALRM and set the
    'progress_update' flag explicitly based in the input instructions.
    This way the progress line will be updated deterministically when
    the test wants it to be updated.

  - Specify the time elapsed since start_progress() to make the
    throughput rate calculations deterministic.

Add the new test script 't0500-progress-display.sh' to check a few
simple cases with and without throughput, and that a shorter progress
line properly covers up the previously displayed line in different
situations.

[1] See commits 545dc345eb (progress: break too long progress bar
    lines, 2019-04-12) and 9f1fd84e15 (progress: clear previous
    progress update dynamically, 2019-04-12).
[2] 1aed1a5f25 (progress: avoid empty line when breaking the progress
    line, 2019-05-19)

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 286 insertions, 0 deletions

diff --git a/t/t0500-progress-display.sh b/t/t0500-progress-display.sh
new file mode 100755
index 0000000000..24ccbd8d3b
--- /dev/null
+++ b/t/t0500-progress-display.sh
@@ -0,0 +1,286 @@
+#!/bin/sh
+
+test_description='progress display'
+
+. ./test-lib.sh
+
+show_cr () {
+	tr '\015' Q | sed -e "s/Q/<CR>\\$LF/g"
+}
+
+test_expect_success 'simple progress display' '
+	cat >expect <<-\EOF &&
+	Working hard: 1<CR>
+	Working hard: 2<CR>
+	Working hard: 5<CR>
+	Working hard: 5, done.
+	EOF
+
+	cat >in <<-\EOF &&
+	update
+	progress 1
+	update
+	progress 2
+	progress 3
+	progress 4
+	update
+	progress 5
+	EOF
+	test-tool progress "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display with total' '
+	cat >expect <<-\EOF &&
+	Working hard:  33% (1/3)<CR>
+	Working hard:  66% (2/3)<CR>
+	Working hard: 100% (3/3)<CR>
+	Working hard: 100% (3/3), done.
+	EOF
+
+	cat >in <<-\EOF &&
+	progress 1
+	progress 2
+	progress 3
+	EOF
+	test-tool progress --total=3 "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display breaks long lines #1' '
+	sed -e "s/Z$//" >expect <<\EOF &&
+Working hard.......2.........3.........4.........5.........6:   0% (100/100000)<CR>
+Working hard.......2.........3.........4.........5.........6:   1% (1000/100000)<CR>
+Working hard.......2.........3.........4.........5.........6:                   Z
+   10% (10000/100000)<CR>
+  100% (100000/100000)<CR>
+  100% (100000/100000), done.
+EOF
+
+	cat >in <<-\EOF &&
+	progress 100
+	progress 1000
+	progress 10000
+	progress 100000
+	EOF
+	test-tool progress --total=100000 \
+		"Working hard.......2.........3.........4.........5.........6" \
+		<in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display breaks long lines #2' '
+	# Note: we dont need that many spaces after the title to cover up
+	# the last line before breaking the progress line.
+	sed -e "s/Z$//" >expect <<\EOF &&
+Working hard.......2.........3.........4.........5.........6:   0% (1/100000)<CR>
+Working hard.......2.........3.........4.........5.........6:   0% (2/100000)<CR>
+Working hard.......2.........3.........4.........5.........6:                   Z
+   10% (10000/100000)<CR>
+  100% (100000/100000)<CR>
+  100% (100000/100000), done.
+EOF
+
+	cat >in <<-\EOF &&
+	update
+	progress 1
+	update
+	progress 2
+	progress 10000
+	progress 100000
+	EOF
+	test-tool progress --total=100000 \
+		"Working hard.......2.........3.........4.........5.........6" \
+		<in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display breaks long lines #3 - even the first is too long' '
+	# Note: we dont actually need any spaces at the end of the title
+	# line, because there is no previous progress line to cover up.
+	sed -e "s/Z$//" >expect <<\EOF &&
+Working hard.......2.........3.........4.........5.........6:                   Z
+   25% (25000/100000)<CR>
+   50% (50000/100000)<CR>
+   75% (75000/100000)<CR>
+  100% (100000/100000)<CR>
+  100% (100000/100000), done.
+EOF
+
+	cat >in <<-\EOF &&
+	progress 25000
+	progress 50000
+	progress 75000
+	progress 100000
+	EOF
+	test-tool progress --total=100000 \
+		"Working hard.......2.........3.........4.........5.........6" \
+		<in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display breaks long lines #4 - title line matches terminal width' '
+	cat >expect <<\EOF &&
+Working hard.......2.........3.........4.........5.........6.........7.........:
+   25% (25000/100000)<CR>
+   50% (50000/100000)<CR>
+   75% (75000/100000)<CR>
+  100% (100000/100000)<CR>
+  100% (100000/100000), done.
+EOF
+
+	cat >in <<-\EOF &&
+	progress 25000
+	progress 50000
+	progress 75000
+	progress 100000
+	EOF
+	test-tool progress --total=100000 \
+		"Working hard.......2.........3.........4.........5.........6.........7........." \
+		<in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+# Progress counter goes backwards, this should not happen in practice.
+test_expect_success 'progress shortens - crazy caller' '
+	cat >expect <<-\EOF &&
+	Working hard:  10% (100/1000)<CR>
+	Working hard:  20% (200/1000)<CR>
+	Working hard:   0% (1/1000)  <CR>
+	Working hard: 100% (1000/1000)<CR>
+	Working hard: 100% (1000/1000), done.
+	EOF
+
+	cat >in <<-\EOF &&
+	progress 100
+	progress 200
+	progress 1
+	progress 1000
+	EOF
+	test-tool progress --total=1000 "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display with throughput' '
+	cat >expect <<-\EOF &&
+	Working hard: 10<CR>
+	Working hard: 20, 200.00 KiB | 100.00 KiB/s<CR>
+	Working hard: 30, 300.00 KiB | 100.00 KiB/s<CR>
+	Working hard: 40, 400.00 KiB | 100.00 KiB/s<CR>
+	Working hard: 40, 400.00 KiB | 100.00 KiB/s, done.
+	EOF
+
+	cat >in <<-\EOF &&
+	throughput 102400 1000
+	update
+	progress 10
+	throughput 204800 2000
+	update
+	progress 20
+	throughput 307200 3000
+	update
+	progress 30
+	throughput 409600 4000
+	update
+	progress 40
+	EOF
+	test-tool progress "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'progress display with throughput and total' '
+	cat >expect <<-\EOF &&
+	Working hard:  25% (10/40)<CR>
+	Working hard:  50% (20/40), 200.00 KiB | 100.00 KiB/s<CR>
+	Working hard:  75% (30/40), 300.00 KiB | 100.00 KiB/s<CR>
+	Working hard: 100% (40/40), 400.00 KiB | 100.00 KiB/s<CR>
+	Working hard: 100% (40/40), 400.00 KiB | 100.00 KiB/s, done.
+	EOF
+
+	cat >in <<-\EOF &&
+	throughput 102400 1000
+	progress 10
+	throughput 204800 2000
+	progress 20
+	throughput 307200 3000
+	progress 30
+	throughput 409600 4000
+	progress 40
+	EOF
+	test-tool progress --total=40 "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'cover up after throughput shortens' '
+	cat >expect <<-\EOF &&
+	Working hard: 1<CR>
+	Working hard: 2, 800.00 KiB | 400.00 KiB/s<CR>
+	Working hard: 3, 1.17 MiB | 400.00 KiB/s  <CR>
+	Working hard: 4, 1.56 MiB | 400.00 KiB/s<CR>
+	Working hard: 4, 1.56 MiB | 400.00 KiB/s, done.
+	EOF
+
+	cat >in <<-\EOF &&
+	throughput 409600 1000
+	update
+	progress 1
+	throughput 819200 2000
+	update
+	progress 2
+	throughput 1228800 3000
+	update
+	progress 3
+	throughput 1638400 4000
+	update
+	progress 4
+	EOF
+	test-tool progress "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_expect_success 'cover up after throughput shortens a lot' '
+	cat >expect <<-\EOF &&
+	Working hard: 1<CR>
+	Working hard: 2, 1000.00 KiB | 1000.00 KiB/s<CR>
+	Working hard: 3, 3.00 MiB | 1.50 MiB/s      <CR>
+	Working hard: 3, 3.00 MiB | 1024.00 KiB/s, done.
+	EOF
+
+	cat >in <<-\EOF &&
+	throughput 1 1000
+	update
+	progress 1
+	throughput 1024000 2000
+	update
+	progress 2
+	throughput 3145728 3000
+	update
+	progress 3
+	EOF
+	test-tool progress "Working hard" <in 2>stderr &&
+
+	show_cr <stderr >out &&
+	test_i18ncmp expect out
+'
+
+test_done