[PATCH v3 01/11] t: add tool to translate hash-related values

["brian m. carlson" <sandals@crustytoothpaste.net>]

Add a test function helper, test_oid, that produces output that varies
depending on the hash in use.  Add two additional helpers,
test_oid_cache, which can be used to load data for test_oid from
standard input, and test_oid_init, which can be used to load certain
fixed values from lookup charts.  Check that these functions work in
t0000, as the rest of the testsuite will soon come to depend on them.

Implement two basic lookup charts, one for common invalid or synthesized
object IDs, and one for various facts about the hash function in use.
Provide versions for both SHA-1 and SHA-256.

Note that due to the implementation used, names used for lookup can
currently consist only of shell identifier characters.  If this is a
problem in the future, we can hash the names before use.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 t/oid-info/hash-info    |  8 ++++++++
 t/oid-info/oid          | 29 +++++++++++++++++++++++++++
 t/t0000-basic.sh        | 35 ++++++++++++++++++++++++++++++++
 t/test-lib-functions.sh | 44 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 116 insertions(+)
 create mode 100644 t/oid-info/hash-info
 create mode 100644 t/oid-info/oid

diff --git a/t/oid-info/hash-info b/t/oid-info/hash-info
new file mode 100644
index 0000000000..ccdbfdf974
--- /dev/null
+++ b/t/oid-info/hash-info
@@ -0,0 +1,8 @@
+rawsz sha1:20
+rawsz sha256:32
+
+hexsz sha1:40
+hexsz sha256:64
+
+zero sha1:0000000000000000000000000000000000000000
+zero sha256:0000000000000000000000000000000000000000000000000000000000000000
diff --git a/t/oid-info/oid b/t/oid-info/oid
new file mode 100644
index 0000000000..a754970523
--- /dev/null
+++ b/t/oid-info/oid
@@ -0,0 +1,29 @@
+# These are some common invalid and partial object IDs used in tests.
+001	sha1:0000000000000000000000000000000000000001
+001	sha256:0000000000000000000000000000000000000000000000000000000000000001
+002	sha1:0000000000000000000000000000000000000002
+002	sha256:0000000000000000000000000000000000000000000000000000000000000002
+003	sha1:0000000000000000000000000000000000000003
+003	sha256:0000000000000000000000000000000000000000000000000000000000000003
+004	sha1:0000000000000000000000000000000000000004
+004	sha256:0000000000000000000000000000000000000000000000000000000000000004
+005	sha1:0000000000000000000000000000000000000005
+005	sha256:0000000000000000000000000000000000000000000000000000000000000005
+006	sha1:0000000000000000000000000000000000000006
+006	sha256:0000000000000000000000000000000000000000000000000000000000000006
+007	sha1:0000000000000000000000000000000000000007
+007	sha256:0000000000000000000000000000000000000000000000000000000000000007
+# All zeros or Fs missing one or two hex segments.
+zero_1		sha1:000000000000000000000000000000000000000
+zero_1		sha256:000000000000000000000000000000000000000000000000000000000000000
+zero_2		sha1:00000000000000000000000000000000000000
+zero_2		sha256:00000000000000000000000000000000000000000000000000000000000000
+ff_1		sha1:fffffffffffffffffffffffffffffffffffffff
+ff_1		sha256:fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+ff_2		sha1:ffffffffffffffffffffffffffffffffffffff
+ff_2		sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+# More various invalid OIDs.
+numeric		sha1:0123456789012345678901234567890123456789
+numeric		sha256:0123456789012345678901234567890123456789012345678901234567890123
+deadbeef	sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef
+deadbeef	sha256:deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 850f651e4e..e3cace299e 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -821,6 +821,41 @@ test_expect_success 'tests clean up even on failures' "
 	EOF
 "
 
+test_oid_init
+
+test_expect_success 'test_oid provides sane info by default' '
+	test_oid zero >actual &&
+	grep "^00*$" actual &&
+	rawsz="$(test_oid rawsz)" &&
+	hexsz="$(test_oid hexsz)" &&
+	test "$hexsz" -eq $(wc -c <actual) &&
+	test $(( $rawsz * 2)) -eq "$hexsz"
+'
+
+test_expect_success 'test_oid can look up data for SHA-1' '
+	test_when_finished "test_detect_hash" &&
+	test_set_hash sha1 &&
+	test_oid zero >actual &&
+	grep "^00*$" actual &&
+	rawsz="$(test_oid rawsz)" &&
+	hexsz="$(test_oid hexsz)" &&
+	test $(wc -c <actual) -eq 40 &&
+	test "$rawsz" -eq 20 &&
+	test "$hexsz" -eq 40
+'
+
+test_expect_success 'test_oid can look up data for SHA-256' '
+	test_when_finished "test_detect_hash" &&
+	test_set_hash sha256 &&
+	test_oid zero >actual &&
+	grep "^00*$" actual &&
+	rawsz="$(test_oid rawsz)" &&
+	hexsz="$(test_oid hexsz)" &&
+	test $(wc -c <actual) -eq 64 &&
+	test "$rawsz" -eq 32 &&
+	test "$hexsz" -eq 64
+'
+
 ################################################################
 # Basics of the basics
 
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 4207af4077..2300ec49dd 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1155,3 +1155,47 @@ depacketize () {
 		}
 	'
 }
+
+test_set_hash () {
+	test_hash_algo="$1"
+}
+
+test_detect_hash () {
+	test_hash_algo='sha1'
+}
+
+test_oid_init () {
+	test_oid_cache <"$TEST_DIRECTORY/oid-info/hash-info" &&
+	test_oid_cache <"$TEST_DIRECTORY/oid-info/oid"
+}
+
+test_oid_cache () {
+	test -n "$test_hash_algo" || test_detect_hash
+	while read _tag _rest
+	do
+		case $_tag in
+		\#*)
+			continue;;
+		?*)
+			# non-empty
+			;;
+		*)
+			# blank line
+			continue;;
+
+		esac &&
+
+		_k="${_rest%:*}" &&
+		_v="${_rest#*:}" &&
+		{ echo "$_k" | egrep '^[a-z0-9]+$' >/dev/null ||
+			error 'bug in the test script: bad hash algorithm'; } &&
+		eval "test_oid_${_k}_$_tag=\"\$_v\"" || return 1
+	done
+}
+
+test_oid () {
+	eval "
+		test -n \"\${test_oid_${test_hash_algo}_$1+set}\" &&
+		printf '%s' \"\${test_oid_${test_hash_algo}_$1}\"
+	"
+}