blame,cat-file: Prepare --textconv tests for correctly-failing conversion program

The textconv filter is sometimes incorrectly ran on a temporary file
whose content is the target of a symbolic link, instead of actual file
content. Prepare to test this by marking the content of the file to
convert with "bin:", and let the helper die if "bin:" is not found in
the file content.

NOTE: I've changed $@ to $1 in helper becase textconv program "should
take a single argument" (see Documentation/gitattributes.txt), so
making this more explicit makes sense and also helps to avoid
problems with feeding arguments to echo.

Signed-off-by: Kirill Smelkov <kirr@landau.phys.spbu.ru>
Reviewed-by: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t8006-blame-textconv.sh

@@ -9,22 +9,23 @@ find_blame() {
 
 cat >helper <<'EOF'
 #!/bin/sh
-sed 's/^/converted: /' "$@"
+grep -q '^bin: ' "$1" || { echo "E: $1 is not \"binary\" file" 1>&2; exit 1; }
+sed 's/^bin: /converted: /' "$1"
 EOF
 chmod +x helper
 
 test_expect_success 'setup ' '
-	echo test 1 >one.bin &&
-	echo test number 2 >two.bin &&
+	echo "bin: test 1" >one.bin &&
+	echo "bin: test number 2" >two.bin &&
 	git add . &&
 	GIT_AUTHOR_NAME=Number1 git commit -a -m First --date="2010-01-01 18:00:00" &&
-	echo test 1 version 2 >one.bin &&
-	echo test number 2 version 2 >>two.bin &&
+	echo "bin: test 1 version 2" >one.bin &&
+	echo "bin: test number 2 version 2" >>two.bin &&
 	GIT_AUTHOR_NAME=Number2 git commit -a -m Second --date="2010-01-01 20:00:00"
 '
 
 cat >expected <<EOF
-(Number2 2010-01-01 20:00:00 +0000 1) test 1 version 2
+(Number2 2010-01-01 20:00:00 +0000 1) bin: test 1 version 2
 EOF
 
 test_expect_success 'no filter specified' '
@@ -67,7 +68,7 @@ test_expect_success 'blame --textconv going through revisions' '
 '
 
 test_expect_success 'make a new commit' '
-	echo "test number 2 version 3" >>two.bin &&
+	echo "bin: test number 2 version 3" >>two.bin &&
 	GIT_AUTHOR_NAME=Number3 git commit -a -m Third --date="2010-01-01 22:00:00"
 '
 

t/t8007-cat-file-textconv.sh

@@ -5,15 +5,16 @@ test_description='git cat-file textconv support'
 
 cat >helper <<'EOF'
 #!/bin/sh
-sed 's/^/converted: /' "$@"
+grep -q '^bin: ' "$1" || { echo "E: $1 is not \"binary\" file" 1>&2; exit 1; }
+sed 's/^bin: /converted: /' "$1"
 EOF
 chmod +x helper
 
 test_expect_success 'setup ' '
-	echo test >one.bin &&
+	echo "bin: test" >one.bin &&
 	git add . &&
 	GIT_AUTHOR_NAME=Number1 git commit -a -m First --date="2010-01-01 18:00:00" &&
-	echo test version 2 >one.bin &&
+	echo "bin: test version 2" >one.bin &&
 	GIT_AUTHOR_NAME=Number2 git commit -a -m Second --date="2010-01-01 20:00:00"
 '
 
@@ -33,7 +34,7 @@ test_expect_success 'setup textconv filters' '
 '
 
 cat >expected <<EOF
-test version 2
+bin: test version 2
 EOF
 
 test_expect_success 'cat-file without --textconv' '
@@ -42,7 +43,7 @@ test_expect_success 'cat-file without --textconv' '
 '
 
 cat >expected <<EOF
-test
+bin: test
 EOF
 
 test_expect_success 'cat-file without --textconv on previous commit' '