tests: make 'test_oid' print trailing newline

Unlike other test helper functions, 'test_oid' doesn't terminate its
output with a LF, but, alas, the reason for this, if any, is not
mentioned in 2c02b110da (t: add test functions to translate
hash-related values, 2018-09-13)).

Now, in the vast majority of cases 'test_oid' is invoked in a command
substitution that is part of a heredoc or supplies an argument to a
command or the value to a variable, and the command substitution would
chop off any trailing LFs, so in these cases the lack or presence of a
trailing LF in its output doesn't matter.  However:

  - There appear to be only three cases where 'test_oid' is not
    invoked in a command substitution:

      $ git grep '\stest_oid ' -- ':/t/*.sh'
      t0000-basic.sh:  test_oid zero >actual &&
      t0000-basic.sh:  test_oid zero >actual &&
      t0000-basic.sh:  test_oid zero >actual &&

    These are all in test cases checking that 'test_oid' actually
    works, and that the size of its output matches the size of the
    corresponding hash function with conditions like

      test $(wc -c <actual) -eq 40

    In these cases the lack of trailing LF does actually matter,
    though they could be trivially updated to account for the presence
    of a trailing LF.

  - There are also a few cases where the lack of trailing LF in
    'test_oid's output actually hurts, because tests need to compare
    its output with LF terminated file contents, forcing developers to
    invoke it as 'echo $(test_oid ...)' to append the missing LF:

      $ git grep 'echo "\?$(test_oid ' -- ':/t/*.sh'
      t1302-repo-version.sh:  echo $(test_oid version) >expect &&
      t1500-rev-parse.sh:     echo "$(test_oid algo)" >expect &&
      t4044-diff-index-unique-abbrev.sh:      echo "$(test_oid val1)" > foo &&
      t4044-diff-index-unique-abbrev.sh:      echo "$(test_oid val2)" > foo &&
      t5313-pack-bounds-checks.sh:    echo $(test_oid oidfff) >file &&

    And there is yet another similar case in an in-flight topic at:

      https://public-inbox.org/git/813e81a058227bd373cec802e443fcd677042fb4.1670862677.git.gitgitgadget@gmail.com/

Arguably we would be better off if 'test_oid' terminated its output
with a LF.  So let's update 'test_oid' accordingly, update its tests
in t0000 to account for the extra character in those size tests, and
remove the now unnecessary 'echo $(...)' command substitutions around
'test_oid' invocations as well.

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

t/t0000-basic.sh

@@ -815,7 +815,8 @@ test_expect_success 'test_oid provides sane info by default' '
 	grep "^00*\$" actual &&
 	rawsz="$(test_oid rawsz)" &&
 	hexsz="$(test_oid hexsz)" &&
-	test "$hexsz" -eq $(wc -c <actual) &&
+	# +1 accounts for the trailing newline
+	test $(( $hexsz + 1)) -eq $(wc -c <actual) &&
 	test $(( $rawsz * 2)) -eq "$hexsz"
 '
 
@@ -826,7 +827,7 @@ test_expect_success 'test_oid can look up data for SHA-1' '
 	grep "^00*\$" actual &&
 	rawsz="$(test_oid rawsz)" &&
 	hexsz="$(test_oid hexsz)" &&
-	test $(wc -c <actual) -eq 40 &&
+	test $(wc -c <actual) -eq 41 &&
 	test "$rawsz" -eq 20 &&
 	test "$hexsz" -eq 40
 '
@@ -838,7 +839,7 @@ test_expect_success 'test_oid can look up data for SHA-256' '
 	grep "^00*\$" actual &&
 	rawsz="$(test_oid rawsz)" &&
 	hexsz="$(test_oid hexsz)" &&
-	test $(wc -c <actual) -eq 64 &&
+	test $(wc -c <actual) -eq 65 &&
 	test "$rawsz" -eq 32 &&
 	test "$hexsz" -eq 64
 '

t/t1302-repo-version.sh

@@ -27,7 +27,7 @@ test_expect_success 'setup' '
 '
 
 test_expect_success 'gitdir selection on normal repos' '
-	echo $(test_oid version) >expect &&
+	test_oid version >expect &&
 	git config core.repositoryformatversion >actual &&
 	git -C test config core.repositoryformatversion >actual2 &&
 	test_cmp expect actual &&

t/t1500-rev-parse.sh

@@ -195,7 +195,7 @@ test_expect_success 'rev-parse --is-shallow-repository in non-shallow repo' '
 '
 
 test_expect_success 'rev-parse --show-object-format in repo' '
-	echo "$(test_oid algo)" >expect &&
+	test_oid algo >expect &&
 	git rev-parse --show-object-format >actual &&
 	test_cmp expect actual &&
 	git rev-parse --show-object-format=storage >actual &&

t/t4044-diff-index-unique-abbrev.sh

@@ -34,12 +34,12 @@ test_expect_success 'setup' '
 	100644 blob $(test_oid hash2)	foo
 	EOF
 
-	echo "$(test_oid val1)" > foo &&
+	test_oid val1 > foo &&
 	git add foo &&
 	git commit -m "initial" &&
 	git cat-file -p HEAD: > actual &&
 	test_cmp expect_initial actual &&
-	echo "$(test_oid val2)" > foo &&
+	test_oid val2 > foo &&
 	git commit -a -m "update" &&
 	git cat-file -p HEAD: > actual &&
 	test_cmp expect_update actual

t/t5313-pack-bounds-checks.sh

@@ -59,7 +59,7 @@ test_expect_success 'setup' '
 test_expect_success 'set up base packfile and variables' '
 	# the hash of this content starts with ff, which
 	# makes some later computations much simpler
-	echo $(test_oid oidfff) >file &&
+	test_oid oidfff >file &&
 	git add file &&
 	git commit -m base &&
 	git repack -ad &&

t/test-lib-functions.sh

@@ -1682,7 +1682,7 @@ test_oid () {
 	then
 		BUG "undefined key '$1'"
 	fi &&
-	eval "printf '%s' \"\${$var}\""
+	eval "printf '%s\n' \"\${$var}\""
 }
 
 # Insert a slash into an object ID so it can be used to reference a location