[llvm-strings] Improve testing of llvm-strings

This patch tidies up the llvm-strings testing by:

1. Adding comments to every test.
2. Getting rid of canned input files, and having the tests generate
   them on the fly (this makes the tests self-contained).
3. Adding missing test coverage.
4. Renaming some tests that weren't clear as to their purpose.
5. Adding extra checking of various cases, formatting etc.
6. Removing a test that didn't seem to have any useful purpose for
   testing llvm-strings.

Reviewed by: rupprecht, grimar, MaskRay

Differential Revision: https://reviews.llvm.org/D66015

llvm-svn: 368555

23 files changed, 216 insertions, 93 deletions

diff --git a/llvm/test/tools/llvm-strings/Inputs/abcd b/llvm/test/tools/llvm-strings/Inputs/abcd
deleted file mode 100644
index 85df50785d6..00000000000
--- a/llvm/test/tools/llvm-strings/Inputs/abcd
+++ /dev/null
@@ -1 +0,0 @@
-abcd
\ No newline at end of file
diff --git a/llvm/test/tools/llvm-strings/Inputs/numbers b/llvm/test/tools/llvm-strings/Inputs/numbers
deleted file mode 100644
index c9e9e05f445..00000000000
--- a/llvm/test/tools/llvm-strings/Inputs/numbers
+++ /dev/null
@@ -1,10 +0,0 @@
-one
-two
-three
-four
-five
-six
-seven
-eight
-nine
-ten
diff --git a/llvm/test/tools/llvm-strings/Inputs/variable-length b/llvm/test/tools/llvm-strings/Inputs/variable-length
deleted file mode 100644
index 649f68c12db..00000000000
--- a/llvm/test/tools/llvm-strings/Inputs/variable-length
+++ /dev/null
@@ -1,4 +0,0 @@
-a
-ab
-abc
-abcd
diff --git a/llvm/test/tools/llvm-strings/all-sections.test b/llvm/test/tools/llvm-strings/all-sections.test
index dcf351913d3..afd3f2823bb 100644
--- a/llvm/test/tools/llvm-strings/all-sections.test
+++ b/llvm/test/tools/llvm-strings/all-sections.test
@@ -1,3 +1,7 @@
-RUN: llvm-strings -a %S/Inputs/abcd | FileCheck %s
-RUN: llvm-strings --all %S/Inputs/abcd | FileCheck %s
+## Show that the -a/--all switch is accepted. GNU strings checks specific object
+## file sections unless --all is specified. llvm-strings just looks at the entire
+## file, so this option is silently ignored.
+
+RUN: echo abcd | llvm-strings -a | FileCheck %s
+RUN: echo abcd | llvm-strings --all | FileCheck %s
 CHECK: abcd
diff --git a/llvm/test/tools/llvm-strings/archive-filename.test b/llvm/test/tools/llvm-strings/archive-filename.test
index 371525bbf51..f439c8460fa 100644
--- a/llvm/test/tools/llvm-strings/archive-filename.test
+++ b/llvm/test/tools/llvm-strings/archive-filename.test
@@ -1,9 +1,12 @@
+## Show that --print-file-name prints just the archive name for an archive and
+## not the member names.
+
 RUN: rm -rf %t && mkdir -p %t
-RUN: llvm-ar --format=gnu crs %t/archive.a %S/Inputs/abcd
+RUN: echo -n abcd > %t/abcd
+RUN: llvm-ar --format=gnu crs %t/archive.a %t/abcd
 RUN: llvm-strings -f %t/archive.a | FileCheck %s
 RUN: llvm-strings --print-file-name %t/archive.a | FileCheck %s
 
 CHECK: archive.a: !<arch>
 CHECK: archive.a: abcd/           0           0     0     644     4         `
 CHECK: archive.a: abcd
-
diff --git a/llvm/test/tools/llvm-strings/eof-no-string.test b/llvm/test/tools/llvm-strings/eof-no-string.test
new file mode 100644
index 00000000000..2a4c29b9223
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/eof-no-string.test
@@ -0,0 +1,5 @@
+## Show that llvm-strings does not print the last string in the input if it is
+## too short and no unprintable character follows it.
+
+RUN: echo -n abc | llvm-strings - | FileCheck --allow-empty %s
+CHECK-NOT: abc
diff --git a/llvm/test/tools/llvm-strings/eof.test b/llvm/test/tools/llvm-strings/eof.test
new file mode 100644
index 00000000000..b3640590f18
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/eof.test
@@ -0,0 +1,5 @@
+## Show that llvm-strings prints the last string in the input even if no
+## unprintable character follows it.
+
+RUN: echo -n abcdefg | llvm-strings - | FileCheck %s
+CHECK: abcdefg
diff --git a/llvm/test/tools/llvm-strings/file-filename.test b/llvm/test/tools/llvm-strings/file-filename.test
index 26f3b4d334f..7284970a4cf 100644
--- a/llvm/test/tools/llvm-strings/file-filename.test
+++ b/llvm/test/tools/llvm-strings/file-filename.test
@@ -1,3 +1,10 @@
-RUN: llvm-strings -f %S/Inputs/abcd | FileCheck %s
-RUN: llvm-strings --print-file-name %S/Inputs/abcd | FileCheck %s --strict-whitespace
-CHECK: {{[\\/]}}abcd: abcd
+## Show that --print-file-name prints the name of the file before each line in
+## the output.
+
+RUN: echo abcd > %t
+RUN: echo efg >> %t
+RUN: echo hijk >> %t
+RUN: llvm-strings -f %t | FileCheck %s --strict-whitespace -DFILE=%t
+RUN: llvm-strings --print-file-name %t | FileCheck %s --strict-whitespace -DFILE=%t
+CHECK:      [[FILE]]: abcd
+CHECK-NEXT: [[FILE]]: hijk
diff --git a/llvm/test/tools/llvm-strings/help.test b/llvm/test/tools/llvm-strings/help.test
index 9c3f932abae..d5d4ca80a4f 100644
--- a/llvm/test/tools/llvm-strings/help.test
+++ b/llvm/test/tools/llvm-strings/help.test
@@ -1,7 +1,15 @@
-RUN: llvm-strings -h | FileCheck %s
-RUN: llvm-strings --help | FileCheck %s
+## Show that help text is printed correctly when requested.
+
+RUN: llvm-strings -h | FileCheck %s --check-prefixes=CHECK,CATEG
+RUN: llvm-strings --help | FileCheck %s --check-prefixes=CHECK,CATEG
+RUN: llvm-strings --help-list \
+RUN:   | FileCheck %s --check-prefixes=CHECK,LIST
 
 CHECK: OVERVIEW: llvm string dumper
 CHECK: USAGE: llvm-strings{{(.exe)?}} [options] <input object files>{{$}}
 CHECK: OPTIONS:
+CATEG:    General options:
+LIST-NOT: General options:
+CATEG:    Generic Options:
+LIST-NOT: Generic Options:
 CHECK: @FILE
diff --git a/llvm/test/tools/llvm-strings/length.test b/llvm/test/tools/llvm-strings/length.test
index 20d586df820..ac25c523c94 100644
--- a/llvm/test/tools/llvm-strings/length.test
+++ b/llvm/test/tools/llvm-strings/length.test
@@ -1,24 +1,46 @@
-RUN: not llvm-strings -n 0 2>&1 %S/Inputs/variable-length | FileCheck --check-prefix CHECK-0 %s
-RUN: llvm-strings -n 1 %S/Inputs/variable-length | FileCheck --check-prefix CHECK-1 %s
-RUN: llvm-strings -n 2 %S/Inputs/variable-length | FileCheck --check-prefix CHECK-2 %s
-RUN: llvm-strings %S/Inputs/variable-length | FileCheck --check-prefix CHECK-DEFAULT %s
+## Show that llvm-strings prints only strings with length of at least the
+## requested number of bytes.
 
-STDIN: a
-STDIN: ab
-STDIN: abc
-STDIN: abcd
+RUN: echo a > %t
+RUN: echo ab >> %t
+RUN: echo abc >> %t
+RUN: echo abcd >> %t
+RUN: echo abcde >> %t
+RUN: not llvm-strings -n 0 2>&1 %t | FileCheck --check-prefix CHECK-0 %s
+RUN: llvm-strings -n 1 %t | FileCheck --check-prefix CHECK-1 %s --implicit-check-not={{.}}
+RUN: llvm-strings -n 2 %t | FileCheck --check-prefix CHECK-2 %s --implicit-check-not={{.}}
+RUN: llvm-strings -n 4 %t | FileCheck --check-prefix CHECK-4 %s --implicit-check-not={{.}}
+RUN: llvm-strings -n 5 %t | FileCheck --check-prefix CHECK-5 %s --implicit-check-not={{.}}
+RUN: llvm-strings -n 6 %t | FileCheck %s --implicit-check-not={{.}} --allow-empty
 
-CHECK-DEFAULT: abcd
+## Default is equivalent to -n 4.
+RUN: llvm-strings %t | FileCheck --check-prefix CHECK-4 %s --implicit-check-not={{.}}
+
+## Show --bytes works too.
+RUN: llvm-strings --bytes 2 %t | FileCheck --check-prefix CHECK-2 %s --implicit-check-not={{.}}
+
+## Show different syntaxes work.
+RUN: llvm-strings --bytes=2 %t | FileCheck --check-prefix CHECK-2 %s --implicit-check-not={{.}}
+RUN: llvm-strings -n=2 %t | FileCheck --check-prefix CHECK-2 %s --implicit-check-not={{.}}
 
 CHECK-0: invalid minimum string length 0
 
-CHECK-1: a
-CHECK-1: ab
-CHECK-1: abc
-CHECK-1: abcd
+CHECK-1:      a
+CHECK-1-NEXT: ab
+CHECK-1-NEXT: abc
+CHECK-1-NEXT: abcd
+CHECK-1-NEXT: abcde
+
+CHECK-2:      ab
+CHECK-2-NEXT: abc
+CHECK-2-NEXT: abcd
+CHECK-2-NEXT: abcde
+
+CHECK-4:      abcd
+CHECK-4-NEXT: abcde
 
-CHECK-2-NOT: a
-CHECK-2: ab
-CHECK-2: abc
-CHECK-2: abcd
+CHECK-5:      abcde
 
+## Show that a non-numeric argument is rejected.
+RUN: not llvm-strings -n foo %t 2>&1 | FileCheck %s --check-prefix=ERR
+ERR: llvm-strings{{.*}}: for the --bytes option: 'foo' value invalid for integer argument!
diff --git a/llvm/test/tools/llvm-strings/multiple-inputs.test b/llvm/test/tools/llvm-strings/multiple-inputs.test
new file mode 100644
index 00000000000..8eeeebfc489
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/multiple-inputs.test
@@ -0,0 +1,13 @@
+## Show that llvm-strings reads every file specified on the command-line.
+## This test uses --print-file-name and --radix to show that the values are
+## updated for the second file.
+
+RUN: echo abcd > %t1
+RUN: echo 1234 >> %t1
+RUN: echo defg > %t2
+RUN: llvm-strings --print-file-name --radix=d %t1 %t2 \
+RUN:   | FileCheck %s -DFILE1=%t1 -DFILE2=%t2 --implicit-check-not={{.}}
+
+CHECK:      [[FILE1]]: 0 abcd
+CHECK-NEXT: [[FILE1]]: 5 1234
+CHECK-NEXT: [[FILE2]]: 0 defg
diff --git a/llvm/test/tools/llvm-strings/negative-char.test b/llvm/test/tools/llvm-strings/negative-char.test
index e91dcda0cca..8c60685bf70 100644
--- a/llvm/test/tools/llvm-strings/negative-char.test
+++ b/llvm/test/tools/llvm-strings/negative-char.test
@@ -1,3 +1,6 @@
+## Show that llvm-strings can handle a negative signed char value (i.e. > 0x7f).
+## Such characters should form string delimiters like other unprintable ones.
+
 # RUN: echo -e "z\0\x80\0a\0" | llvm-strings --bytes 1 - | FileCheck %s
 # CHECK: z{{$}}
 # CHECK-NEXT: {{^}}a
diff --git a/llvm/test/tools/llvm-strings/nested-archives.test b/llvm/test/tools/llvm-strings/nested-archives.test
deleted file mode 100644
index 5bbfae44201..00000000000
--- a/llvm/test/tools/llvm-strings/nested-archives.test
+++ /dev/null
@@ -1,11 +0,0 @@
-RUN: rm -rf %t && mkdir -p %t
-RUN: llvm-ar --format=gnu crs %t/inner.a %S/Inputs/abcd
-RUN: llvm-ar --format=gnu crs %t/outer.a %t/inner.a
-RUN: llvm-strings %t/outer.a | FileCheck %s
-
-CHECK: !<arch>
-CHECK: inner.a/        0           0     0     644     72        `
-CHECK: !<arch>
-CHECK: abcd/           0           0     0     644     4         `
-CHECK: abcd
-
diff --git a/llvm/test/tools/llvm-strings/option-grouping.test b/llvm/test/tools/llvm-strings/option-grouping.test
new file mode 100644
index 00000000000..db4581d7890
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/option-grouping.test
@@ -0,0 +1,6 @@
+## Show that llvm-strings can handle grouped short options.
+
+RUN: echo abcd > %t
+RUN: llvm-strings -af %t | FileCheck %s -DFILE=%t
+
+CHECK: [[FILE]]: abcd
diff --git a/llvm/test/tools/llvm-strings/radix-filename.test b/llvm/test/tools/llvm-strings/radix-filename.test
index 60d78da2a13..d8c3b7aad6b 100644
--- a/llvm/test/tools/llvm-strings/radix-filename.test
+++ b/llvm/test/tools/llvm-strings/radix-filename.test
@@ -1,36 +1,49 @@
-RUN: llvm-strings --print-file-name %S/Inputs/numbers \
-RUN:     | FileCheck %s --check-prefix CHECK-NONE
-RUN: llvm-strings --print-file-name -t d %S/Inputs/numbers \
-RUN:    | FileCheck %s --check-prefix CHECK-DEC --strict-whitespace
-RUN: llvm-strings --print-file-name -t o %S/Inputs/numbers \
-RUN:     | FileCheck %s --check-prefix CHECK-OCT --strict-whitespace
-RUN: llvm-strings --print-file-name -t x %S/Inputs/numbers \
-RUN:     | FileCheck %s --check-prefix CHECK-HEX --strict-whitespace
+## Show that --radix combined with --print-file-name produces correct output.
 
-CHECK-NONE: numbers: three
-CHECK-NONE: numbers: four
-CHECK-NONE: numbers: five
-CHECK-NONE: numbers: seven
-CHECK-NONE: numbers: eight
-CHECK-NONE: numbers: nine
+RUN: echo one > %t
+RUN: echo two >> %t
+RUN: echo three >> %t
+RUN: echo four >> %t
+RUN: echo five >> %t
+RUN: echo six >> %t
+RUN: echo seven >> %t
+RUN: echo eight >> %t
+RUN: echo nine >> %t
+RUN: echo ten >> %t
 
-CHECK-DEC: numbers:       8 three
-CHECK-DEC: numbers:      14 four
-CHECK-DEC: numbers:      19 five
-CHECK-DEC: numbers:      28 seven
-CHECK-DEC: numbers:      34 eight
-CHECK-DEC: numbers:      40 nine
+RUN: llvm-strings --print-file-name %t \
+RUN:     | FileCheck %s --check-prefix CHECK-NONE -DFILE=%t --implicit-check-not={{.}}
+RUN: llvm-strings --print-file-name -t d %t \
+RUN:    | FileCheck %s --check-prefix CHECK-DEC --strict-whitespace -DFILE=%t --implicit-check-not={{.}}
+RUN: llvm-strings --print-file-name -t o %t \
+RUN:     | FileCheck %s --check-prefix CHECK-OCT --strict-whitespace -DFILE=%t --implicit-check-not={{.}}
+RUN: llvm-strings --print-file-name -t x %t \
+RUN:     | FileCheck %s --check-prefix CHECK-HEX --strict-whitespace -DFILE=%t --implicit-check-not={{.}}
 
-CHECK-OCT: numbers:      10 three
-CHECK-OCT: numbers:      16 four
-CHECK-OCT: numbers:      23 five
-CHECK-OCT: numbers:      34 seven
-CHECK-OCT: numbers:      42 eight
-CHECK-OCT: numbers:      50 nine
+CHECK-NONE: [[FILE]]: three
+CHECK-NONE: [[FILE]]: four
+CHECK-NONE: [[FILE]]: five
+CHECK-NONE: [[FILE]]: seven
+CHECK-NONE: [[FILE]]: eight
+CHECK-NONE: [[FILE]]: nine
 
-CHECK-HEX: numbers:       8 three
-CHECK-HEX: numbers:       e four
-CHECK-HEX: numbers:      13 five
-CHECK-HEX: numbers:      1c seven
-CHECK-HEX: numbers:      22 eight
-CHECK-HEX: numbers:      28 nine
+CHECK-DEC: [[FILE]]:       8 three
+CHECK-DEC: [[FILE]]:      14 four
+CHECK-DEC: [[FILE]]:      19 five
+CHECK-DEC: [[FILE]]:      28 seven
+CHECK-DEC: [[FILE]]:      34 eight
+CHECK-DEC: [[FILE]]:      40 nine
+
+CHECK-OCT: [[FILE]]:      10 three
+CHECK-OCT: [[FILE]]:      16 four
+CHECK-OCT: [[FILE]]:      23 five
+CHECK-OCT: [[FILE]]:      34 seven
+CHECK-OCT: [[FILE]]:      42 eight
+CHECK-OCT: [[FILE]]:      50 nine
+
+CHECK-HEX: [[FILE]]:       8 three
+CHECK-HEX: [[FILE]]:       e four
+CHECK-HEX: [[FILE]]:      13 five
+CHECK-HEX: [[FILE]]:      1c seven
+CHECK-HEX: [[FILE]]:      22 eight
+CHECK-HEX: [[FILE]]:      28 nine
diff --git a/llvm/test/tools/llvm-strings/radix.test b/llvm/test/tools/llvm-strings/radix.test
index 403b8580805..d23fb3cddc8 100644
--- a/llvm/test/tools/llvm-strings/radix.test
+++ b/llvm/test/tools/llvm-strings/radix.test
@@ -1,7 +1,29 @@
-RUN: llvm-strings %S/Inputs/numbers | FileCheck %s -check-prefix CHECK-NONE
-RUN: llvm-strings -t d %S/Inputs/numbers | FileCheck %s -check-prefix CHECK-DEC --strict-whitespace
-RUN: llvm-strings -t o %S/Inputs/numbers | FileCheck %s -check-prefix CHECK-OCT --strict-whitespace
-RUN: llvm-strings -t x %S/Inputs/numbers | FileCheck %s -check-prefix CHECK-HEX --strict-whitespace
+## Show that llvm-strings can handle the -t/--radix switch properly.
+
+RUN: echo one > %t
+RUN: echo two >> %t
+RUN: echo three >> %t
+RUN: echo four >> %t
+RUN: echo five >> %t
+RUN: echo six >> %t
+RUN: echo seven >> %t
+RUN: echo eight >> %t
+RUN: echo nine >> %t
+RUN: echo ten >> %t
+
+RUN: llvm-strings %t | FileCheck %s -check-prefix CHECK-NONE --implicit-check-not={{.}}
+RUN: llvm-strings -t d %t | FileCheck %s -check-prefix CHECK-DEC --strict-whitespace --implicit-check-not={{.}}
+RUN: llvm-strings -t o %t | FileCheck %s -check-prefix CHECK-OCT --strict-whitespace --implicit-check-not={{.}}
+RUN: llvm-strings -t x %t | FileCheck %s -check-prefix CHECK-HEX --strict-whitespace --implicit-check-not={{.}}
+
+## Show --radix works too.
+RUN: llvm-strings --radix d %t | FileCheck %s -check-prefix CHECK-DEC --strict-whitespace
+RUN: llvm-strings --radix o %t | FileCheck %s -check-prefix CHECK-OCT --strict-whitespace
+RUN: llvm-strings --radix x %t | FileCheck %s -check-prefix CHECK-HEX --strict-whitespace
+
+## Show different syntaxes work.
+RUN: llvm-strings --radix=d %t | FileCheck %s -check-prefix CHECK-DEC --strict-whitespace
+RUN: llvm-strings -t=d %t | FileCheck %s -check-prefix CHECK-DEC --strict-whitespace
 
 CHECK-NONE: {{^}}three
 CHECK-NONE: {{^}}four
@@ -30,3 +52,7 @@ CHECK-HEX: {{^}}     13 five
 CHECK-HEX: {{^}}     1c seven
 CHECK-HEX: {{^}}     22 eight
 CHECK-HEX: {{^}}     28 nine
+
+## Show that an invalid value is rejected.
+RUN: not llvm-strings --radix z %t 2>&1 | FileCheck %s --check-prefix=INVALID
+INVALID: llvm-strings{{.*}}: for the --radix option: Cannot find option named 'z'!
diff --git a/llvm/test/tools/llvm-strings/response-file.test b/llvm/test/tools/llvm-strings/response-file.test
new file mode 100644
index 00000000000..01f0f5715fd
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/response-file.test
@@ -0,0 +1,7 @@
+## Show that llvm-strings can consume a response file.
+
+RUN: echo abcd > %t
+RUN: echo --print-file-name %t > %t.rsp
+RUN: llvm-strings --radix=d @%t.rsp | FileCheck %s -DFILE=%t
+
+CHECK: [[FILE]]: 0 abcd
diff --git a/llvm/test/tools/llvm-strings/stdin-filename.test b/llvm/test/tools/llvm-strings/stdin-filename.test
index 9c87e5c45d8..7ba4e90a39a 100644
--- a/llvm/test/tools/llvm-strings/stdin-filename.test
+++ b/llvm/test/tools/llvm-strings/stdin-filename.test
@@ -1,3 +1,7 @@
+## Show that --print-file-name works when the input is standard input.
+
 RUN: echo abcd | llvm-strings -f - | FileCheck %s
+RUN: echo abcd | llvm-strings -f | FileCheck %s
 RUN: echo abcd | llvm-strings --print-file-name - | FileCheck %s
+RUN: echo abcd | llvm-strings --print-file-name | FileCheck %s
 CHECK: {standard input}: abcd
diff --git a/llvm/test/tools/llvm-strings/stdin.test b/llvm/test/tools/llvm-strings/stdin.test
new file mode 100644
index 00000000000..b8ccc12e52f
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/stdin.test
@@ -0,0 +1,22 @@
+## Show that llvm-strings can handle stdin input properly.
+
+## Case 1: output with single string.
+RUN: echo -n "abcdefg" | llvm-strings - | FileCheck %s --check-prefix=CASE1 --implicit-check-not={{.}}
+CASE1: abcdefg
+
+## Case 2: output too short for string.
+RUN: echo -n "abc" | llvm-strings - | FileCheck %s --implicit-check-not={{.}} --allow-empty
+
+## Case 3: output with new line.
+RUN: echo -e "abcd\nefgh" | llvm-strings - | FileCheck %s --check-prefix=CASE3 --implicit-check-not={{.}}
+CASE3:      abcd
+CASE3-NEXT: efgh
+
+## Case 4: output containing unprintable characters.
+RUN: echo -e "abcd\x00ef\x1fghij\x7fklmn" | llvm-strings - | FileCheck %s --check-prefix=CASE4 --implicit-check-not={{.}} 
+CASE4:      abcd
+CASE4-NEXT: ghij
+CASE4-NEXT: klmn
+
+## Case 5: no file name specified is equivalent to explicitly requesting stdin.
+RUN: echo -n "abcdefg" | llvm-strings | FileCheck %s --check-prefix=CASE1 --implicit-check-not={{.}}
diff --git a/llvm/test/tools/llvm-strings/terminator-neg.test b/llvm/test/tools/llvm-strings/terminator-neg.test
deleted file mode 100644
index cdcf52498f6..00000000000
--- a/llvm/test/tools/llvm-strings/terminator-neg.test
+++ /dev/null
@@ -1,2 +0,0 @@
-RUN: echo -n abc | llvm-strings - | FileCheck -allow-empty %s
-CHECK-NOT: abc
diff --git a/llvm/test/tools/llvm-strings/terminator.test b/llvm/test/tools/llvm-strings/terminator.test
deleted file mode 100644
index d27eeebe2e7..00000000000
--- a/llvm/test/tools/llvm-strings/terminator.test
+++ /dev/null
@@ -1,2 +0,0 @@
-RUN: echo -n abcdefg | llvm-strings - | FileCheck %s
-CHECK: abcdefg
diff --git a/llvm/test/tools/llvm-strings/version.test b/llvm/test/tools/llvm-strings/version.test
new file mode 100644
index 00000000000..df4dcfa88a8
--- /dev/null
+++ b/llvm/test/tools/llvm-strings/version.test
@@ -0,0 +1,4 @@
+## Show that --version works for llvm-strings.
+
+RUN: llvm-strings --version | FileCheck %s
+CHECK: version
diff --git a/llvm/test/tools/llvm-strings/whitespace.test b/llvm/test/tools/llvm-strings/whitespace.test
index f34a671e997..7963ff73fb8 100644
--- a/llvm/test/tools/llvm-strings/whitespace.test
+++ b/llvm/test/tools/llvm-strings/whitespace.test
@@ -1,2 +1,3 @@
-RUN: echo -n abcd | llvm-strings - | FileCheck %s --strict-whitespace
+## Show that the default output format matches GNU strings.
+RUN: echo -n abcd | llvm-strings - | FileCheck %s --strict-whitespace --implicit-check-not={{.}}
 CHECK: {{^}}abcd{{$}}