test-lib: allow selecting tests by substring/regex with --run

Many of our test scripts have several "setup" tests.  It's a lot easier
to say

   ./t0050-filesystem.sh --run=setup,9

in order to run all the setup tests as well as test #9, than it is to
track down what all the setup tests are and enter all their numbers in
the list.  Also, I often find myself wanting to run just one or a couple
tests from the test file, but I don't know the numbering of any of the
tests -- to get it I either have to first run the whole test file (or
start counting by hand or figure out some other clever but non-obvious
tricks).  It's really convenient to be able to just look at the test
description(s) and then run

   ./t6416-recursive-corner-cases.sh --run=symlink

or

   ./t6402-merge-rename.sh --run='setup,unnecessary update'

Add such an ability to test selection which relies on merely matching
against the test description.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/README

@@ -258,16 +258,13 @@ For an individual test suite --run could be used to specify that
 only some tests should be run or that some tests should be
 excluded from a run.
 
-The argument for --run is a list of individual test numbers or
-ranges with an optional negation prefix that define what tests in
-a test suite to include in the run.  A range is two numbers
-separated with a dash and matches a range of tests with both ends
-been included.  You may omit the first or the second number to
-mean "from the first test" or "up to the very last test"
-respectively.
-
-Optional prefix of '!' means that the test or a range of tests
-should be excluded from the run.
+The argument for --run, <test-selector>, is a list of description
+substrings or regexes or individual test numbers or ranges with an
+optional negation prefix (of '!') that define what tests in a test
+suite to include (or exclude, if negated) in the run.  A range is two
+numbers separated with a dash and matches a range of tests with both
+ends been included.  You may omit the first or the second number to
+mean "from the first test" or "up to the very last test" respectively.
 
 If --run starts with an unprefixed number or range the initial
 set of tests to run is empty. If the first item starts with '!'
@@ -317,6 +314,18 @@ test in the test suite except from 7 up to 11:
 
     $ sh ./t9200-git-cvsexport-commit.sh --run='!7-11'
 
+Sometimes there may be multiple tests with e.g. "setup" in their name
+that are needed and rather than figuring out the number for all of them
+we can just use "setup" as a substring/regex to match against the test
+description:
+
+    $ sh ./t0050-filesystem.sh --run=setup,9-11
+
+or one could select both the setup tests and the rename ones (assuming all
+relevant tests had those words in their descriptions):
+
+    $ sh ./t0050-filesystem.sh --run=setup,rename
+
 Some tests in a test suite rely on the previous tests performing
 certain actions, specifically some tests are designated as
 "setup" test, so you cannot _arbitrarily_ disable one test and

t/t0000-basic.sh

@@ -705,7 +705,31 @@ test_expect_success '--run empty selectors' "
 	EOF
 "
 
-test_expect_success '--run invalid range start' "
+test_expect_success '--run substring selector' "
+	run_sub_test_lib_test run-substring-selector \
+		'--run empty selectors' \
+		--run='relevant' <<-\\EOF &&
+	test_expect_success \"relevant test\" 'true'
+	for i in 1 2 3 4 5 6
+	do
+		test_expect_success \"other test #\$i\" 'true'
+	done
+	test_done
+	EOF
+	check_sub_test_lib_test run-substring-selector <<-\\EOF
+	> ok 1 - relevant test
+	> ok 2 # skip other test #1 (--run)
+	> ok 3 # skip other test #2 (--run)
+	> ok 4 # skip other test #3 (--run)
+	> ok 5 # skip other test #4 (--run)
+	> ok 6 # skip other test #5 (--run)
+	> ok 7 # skip other test #6 (--run)
+	> # passed all 7 test(s)
+	> 1..7
+	EOF
+"
+
+test_expect_success '--run keyword selection' "
 	run_sub_test_lib_test_err run-inv-range-start \
 		'--run invalid range start' \
 		--run='a-5' <<-\\EOF &&
@@ -735,21 +759,6 @@ test_expect_success '--run invalid range end' "
 	EOF_ERR
 "
 
-test_expect_success '--run invalid selector' "
-	run_sub_test_lib_test_err run-inv-selector \
-		'--run invalid selector' \
-		--run='1?' <<-\\EOF &&
-	test_expect_success \"passing test #1\" 'true'
-	test_done
-	EOF
-	check_sub_test_lib_test_err run-inv-selector \
-		<<-\\EOF_OUT 3<<-\\EOF_ERR
-	> FATAL: Unexpected exit with code 1
-	EOF_OUT
-	> error: --run: invalid non-numeric in test selector: '1?'
-	EOF_ERR
-"
-
 
 test_set_prereq HAVEIT
 haveit=no

t/test-lib.sh

@@ -769,6 +769,8 @@ match_pattern_list () {
 }
 
 match_test_selector_list () {
+	operation="$1"
+	shift
 	title="$1"
 	shift
 	arg="$1"
@@ -805,23 +807,22 @@ match_test_selector_list () {
 			*-*)
 				if expr "z${selector%%-*}" : "z[0-9]*[^0-9]" >/dev/null
 				then
-					echo "error: $title: invalid non-numeric in range" \
+					echo "error: $operation: invalid non-numeric in range" \
 						"start: '$orig_selector'" >&2
 					exit 1
 				fi
 				if expr "z${selector#*-}" : "z[0-9]*[^0-9]" >/dev/null
 				then
-					echo "error: $title: invalid non-numeric in range" \
+					echo "error: $operation: invalid non-numeric in range" \
 						"end: '$orig_selector'" >&2
 					exit 1
 				fi
 				;;
 			*)
 				if expr "z$selector" : "z[0-9]*[^0-9]" >/dev/null
 				then
-					echo "error: $title: invalid non-numeric in test" \
-						"selector: '$orig_selector'" >&2
-					exit 1
+					echo "$title" | grep -q "$selector" && return
+					continue
 				fi
 		esac
 
@@ -1031,7 +1032,7 @@ test_skip () {
 		skipped_reason="GIT_SKIP_TESTS"
 	fi
 	if test -z "$to_skip" && test -n "$run_list" &&
-	   ! match_test_selector_list '--run' $test_count "$run_list"
+	   ! match_test_selector_list '--run' "$1" $test_count "$run_list"
 	then
 		to_skip=t
 		skipped_reason="--run"