Merge branch 'jc/test-prereq'

Teaches the test framework to probe rarely used prerequistes lazily,
and make use of it for detecting SYMLINKS, CASE_INSENSITIVE_FS and
NKD/NKC MacOS x gotcha.

* jc/test-prereq:
  t3910: use the UTF8_NFD_TO_NFC test prereq
  test-lib: provide UTF8 behaviour as a prerequisite
  t0050: use the SYMLINKS test prereq
  t0050: use the CASE_INSENSITIVE_FS test prereq
  test-lib: provide case insensitivity as a prerequisite
  test: allow prerequisite to be evaluated lazily
  test: rename $satisfied to $satisfied_prereq

t/README

@@ -625,6 +625,15 @@ use these, and "test_set_prereq" for how to define your own.
    Git was compiled with USE_LIBPCRE=YesPlease. Wrap any tests
    that use git-grep --perl-regexp or git-grep -P in these.
 
+ - CASE_INSENSITIVE_FS
+
+   Test is run on a case insensitive file system.
+
+ - UTF8_NFD_TO_NFC
+
+   Test is run on a filesystem which converts decomposed utf-8 (nfd)
+   to precomposed utf-8 (nfc).
+
 Tips for Writing Tests
 ----------------------
 

t/t0003-attributes.sh

@@ -123,16 +123,6 @@ test_expect_success 'attribute matching is case insensitive when core.ignorecase
 
 '
 
-test_expect_success 'check whether FS is case-insensitive' '
-	mkdir junk &&
-	echo good >junk/CamelCase &&
-	echo bad >junk/camelcase &&
-	if test "$(cat junk/CamelCase)" != good
-	then
-		test_set_prereq CASE_INSENSITIVE_FS
-	fi
-'
-
 test_expect_success CASE_INSENSITIVE_FS 'additional case insensitivity tests' '
 	test_must_fail attr_check a/B/D/g "a/b/d/*" "-c core.ignorecase=0" &&
 	test_must_fail attr_check A/B/D/NO "a/b/d/*" "-c core.ignorecase=0" &&

t/t0050-filesystem.sh

@@ -7,48 +7,26 @@ test_description='Various filesystem issues'
 auml=$(printf '\303\244')
 aumlcdiar=$(printf '\141\314\210')
 
-case_insensitive=
-unibad=
-no_symlinks=
-test_expect_success 'see what we expect' '
-
-	test_case=test_expect_success &&
-	test_unicode=test_expect_success &&
-	mkdir junk &&
-	echo good >junk/CamelCase &&
-	echo bad >junk/camelcase &&
-	if test "$(cat junk/CamelCase)" != good
+if test_have_prereq CASE_INSENSITIVE_FS
 then
-		test_case=test_expect_failure &&
-		case_insensitive=t
-	fi &&
-	rm -fr junk &&
-	mkdir junk &&
-	>junk/"$auml" &&
-	case "$(cd junk && echo *)" in
-	"$aumlcdiar")
-		test_unicode=test_expect_failure &&
-		unibad=t
-		;;
-	*)	;;
-	esac &&
-	rm -fr junk &&
-	{
-		ln -s x y 2> /dev/null &&
-		test -h y 2> /dev/null ||
-		no_symlinks=1 &&
-		rm -f y
-	}
-'
-
-test "$case_insensitive" &&
 	say "will test on a case insensitive filesystem"
-test "$unibad" &&
+	test_case=test_expect_failure
+else
+	test_case=test_expect_success
+fi
+
+if test_have_prereq UTF8_NFD_TO_NFC
+then
 	say "will test on a unicode corrupting filesystem"
-test "$no_symlinks" &&
+	test_unicode=test_expect_failure
+else
+	test_unicode=test_expect_success
+fi
+
+test_have_prereq SYMLINKS ||
 	say "will test on a filesystem lacking symbolic links"
 
-if test "$case_insensitive"
+if test_have_prereq CASE_INSENSITIVE_FS
 then
 test_expect_success "detection of case insensitive filesystem during repo init" '
 
@@ -62,19 +40,19 @@ test_expect_success "detection of case insensitive filesystem during repo init"
 '
 fi
 
-if test "$no_symlinks"
+if test_have_prereq SYMLINKS
 then
-test_expect_success "detection of filesystem w/o symlink support during repo init" '
-
-	v=$(git config --bool core.symlinks) &&
-	test "$v" = false
-'
-else
 test_expect_success "detection of filesystem w/o symlink support during repo init" '
 
 	test_must_fail git config --bool core.symlinks ||
 	test "$(git config --bool core.symlinks)" = true
 '
+else
+test_expect_success "detection of filesystem w/o symlink support during repo init" '
+
+	v=$(git config --bool core.symlinks) &&
+	test "$v" = false
+'
 fi
 
 test_expect_success "setup case tests" '

t/t3910-mac-os-precompose.sh

@@ -7,24 +7,16 @@ test_description='utf-8 decomposed (nfd) converted to precomposed (nfc)'
 
 . ./test-lib.sh
 
+if ! test_have_prereq UTF8_NFD_TO_NFC
+then
+	skip_all="filesystem does not corrupt utf-8"
+	test_done
+fi
+
+# create utf-8 variables
 Adiarnfc=`printf '\303\204'`
 Adiarnfd=`printf 'A\314\210'`
 
-# check if the feature is compiled in
-mkdir junk &&
->junk/"$Adiarnfc" &&
-case "$(cd junk && echo *)" in
-	"$Adiarnfd")
-	test_nfd=1
-	;;
-	*)	;;
-esac
-rm -rf junk
-
-
-if test "$test_nfd"
-then
-	# create more utf-8 variables
 Odiarnfc=`printf '\303\226'`
 Odiarnfd=`printf 'O\314\210'`
 AEligatu=`printf '\303\206'`
@@ -157,8 +149,5 @@ then
 	precomposeunicode=`git config core.precomposeunicode` &&
 	test "$precomposeunicode" = "true"
 '
-else
-	 say "Skipping nfc/nfd tests"
-fi
 
 test_done

t/test-lib-functions.sh

@@ -221,9 +221,35 @@ write_script () {
 # capital letters by convention).
 
 test_set_prereq () {
-	satisfied="$satisfied$1 "
+	satisfied_prereq="$satisfied_prereq$1 "
+}
+satisfied_prereq=" "
+lazily_testable_prereq= lazily_tested_prereq=
+
+# Usage: test_lazy_prereq PREREQ 'script'
+test_lazy_prereq () {
+	lazily_testable_prereq="$lazily_testable_prereq$1 "
+	eval test_prereq_lazily_$1=\$2
+}
+
+test_run_lazy_prereq_ () {
+	script='
+mkdir -p "$TRASH_DIRECTORY/prereq-test-dir" &&
+(
+	cd "$TRASH_DIRECTORY/prereq-test-dir" &&'"$2"'
+)'
+	say >&3 "checking prerequisite: $1"
+	say >&3 "$script"
+	test_eval_ "$script"
+	eval_ret=$?
+	rm -rf "$TRASH_DIRECTORY/prereq-test-dir"
+	if test "$eval_ret" = 0; then
+		say >&3 "prerequisite $1 ok"
+	else
+		say >&3 "prerequisite $1 not satisfied"
+	fi
+	return $eval_ret
 }
-satisfied=" "
 
 test_have_prereq () {
 	# prerequisites can be concatenated with ','
@@ -238,8 +264,24 @@ test_have_prereq () {
 
 	for prerequisite
 	do
+		case " $lazily_tested_prereq " in
+		*" $prerequisite "*)
+			;;
+		*)
+			case " $lazily_testable_prereq " in
+			*" $prerequisite "*)
+				eval "script=\$test_prereq_lazily_$prerequisite" &&
+				if test_run_lazy_prereq_ "$prerequisite" "$script"
+				then
+					test_set_prereq $prerequisite
+				fi
+				lazily_tested_prereq="$lazily_tested_prereq$prerequisite "
+			esac
+			;;
+		esac
+
 		total_prereq=$(($total_prereq + 1))
-		case $satisfied in
+		case "$satisfied_prereq" in
 		*" $prerequisite "*)
 			ok_prereq=$(($ok_prereq + 1))
 			;;

t/test-lib.sh

@@ -659,9 +659,29 @@ test_i18ngrep () {
 	fi
 }
 
+test_lazy_prereq SYMLINKS '
 	# test whether the filesystem supports symbolic links
-ln -s x y 2>/dev/null && test -h y 2>/dev/null && test_set_prereq SYMLINKS
-rm -f y
+	ln -s x y && test -h y
+'
+
+test_lazy_prereq CASE_INSENSITIVE_FS '
+	echo good >CamelCase &&
+	echo bad >camelcase &&
+	test "$(cat CamelCase)" != good
+'
+
+test_lazy_prereq UTF8_NFD_TO_NFC '
+	# check whether FS converts nfd unicode to nfc
+	auml=$(printf "\303\244")
+	aumlcdiar=$(printf "\141\314\210")
+	>"$auml" &&
+	case "$(echo *)" in
+	"$aumlcdiar")
+		true ;;
+	*)
+		false ;;
+	esac
+'
 
 # When the tests are run as root, permission tests will report that
 # things are writable when they shouldn't be.