t5000: rationalize unzip tests

Factor out a function for checking the contents of ZIP archives.  It
extracts their contents and compares them to the original files.  This
removes some duplicate code.  Tests that just create archives can lose
their UNZIP prerequisite.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5000-tar-tree.sh

@@ -31,6 +31,26 @@ GUNZIP=${GUNZIP:-gzip -d}
 
 SUBSTFORMAT=%H%n
 
+check_zip() {
+	zipfile=$1.zip
+	listfile=$1.lst
+	dir=$1
+	dir_with_prefix=$dir/$2
+
+	test_expect_success UNZIP " extract ZIP archive" "
+		(mkdir $dir && cd $dir && $UNZIP ../$zipfile)
+	"
+
+	test_expect_success UNZIP " validate filenames" "
+		(cd ${dir_with_prefix}a && find .) | sort >$listfile &&
+		test_cmp a.lst $listfile
+	"
+
+	test_expect_success UNZIP " validate file contents" "
+		diff -r a ${dir_with_prefix}a
+	"
+}
+
 test_expect_success \
     'populate workdir' \
     'mkdir a b c &&
@@ -181,10 +201,19 @@ test_expect_success \
       test_cmp a/substfile2 g/prefix/a/substfile2
 '
 
+$UNZIP -v >/dev/null 2>&1
+if [ $? -eq 127 ]; then
+	say "Skipping ZIP tests, because unzip was not found"
+else
+	test_set_prereq UNZIP
+fi
+
 test_expect_success \
     'git archive --format=zip' \
     'git archive --format=zip HEAD >d.zip'
 
+check_zip d
+
 test_expect_success \
     'git archive --format=zip in a bare repo' \
     '(cd bare.git && git archive --format=zip HEAD) >d1.zip'
@@ -207,55 +236,25 @@ test_expect_success 'git archive with --output, override inferred format' '
 	test_cmp b.tar d4.zip
 '
 
-$UNZIP -v >/dev/null 2>&1
-if [ $? -eq 127 ]; then
-	say "Skipping ZIP tests, because unzip was not found"
-else
-	test_set_prereq UNZIP
-fi
-
-test_expect_success UNZIP \
-    'extract ZIP archive' \
-    '(mkdir d && cd d && $UNZIP ../d.zip)'
-
-test_expect_success UNZIP \
-    'validate filenames' \
-    '(cd d/a && find .) | sort >d.lst &&
-     test_cmp a.lst d.lst'
-
-test_expect_success UNZIP \
-    'validate file contents' \
-    'diff -r a d/a'
-
 test_expect_success \
     'git archive --format=zip with prefix' \
     'git archive --format=zip --prefix=prefix/ HEAD >e.zip'
 
-test_expect_success UNZIP \
-    'extract ZIP archive with prefix' \
-    '(mkdir e && cd e && $UNZIP ../e.zip)'
+check_zip e prefix/
 
-test_expect_success UNZIP \
-    'validate filenames with prefix' \
-    '(cd e/prefix/a && find .) | sort >e.lst &&
-     test_cmp a.lst e.lst'
+test_expect_success 'git archive -0 --format=zip on large files' '
+	test_config core.bigfilethreshold 1 &&
+	git archive -0 --format=zip HEAD >large.zip
+'
 
-test_expect_success UNZIP \
-    'validate file contents with prefix' \
-    'diff -r a e/prefix/a'
+check_zip large
 
-test_expect_success UNZIP 'git archive -0 --format=zip on large files' '
-    test_config core.bigfilethreshold 1 &&
-    git archive -0 --format=zip HEAD >large.zip &&
-    (mkdir large && cd large && $UNZIP ../large.zip)
+test_expect_success 'git archive --format=zip on large files' '
+	test_config core.bigfilethreshold 1 &&
+	git archive --format=zip HEAD >large-compressed.zip
 '
 
-test_expect_success UNZIP 'git archive --format=zip on large files' '
-    test_config core.bigfilethreshold 1 &&
-    git archive --format=zip HEAD >large-compressed.zip &&
-    (mkdir large-compressed && cd large-compressed && $UNZIP ../large-compressed.zip) &&
-    test_cmp large-compressed/a/bin/sh large/a/bin/sh
-'
+check_zip large-compressed
 
 test_expect_success \
     'git archive --list outside of a git repo' \