t/chainlint: add chainlint "basic" test cases

The --chain-lint option uses heuristics and knowledge of shell syntax to
detect broken &&-chains in subshells by pure textual inspection. The
heuristics handle a range of stylistic variations in existing tests
(evolved over the years), however, they are still best-guesses. As such,
it is possible for future changes to accidentally break assumptions upon
which the heuristics are based. Protect against this possibility by
adding tests which check the linter itself for correctness.

In addition to protecting against regressions, these tests help document
(for humans) expected behavior, which is important since the linter's
implementation language ('sed') does not necessarily lend itself to easy
comprehension.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

16 files changed, 206 insertions, 0 deletions

diff --git a/t/chainlint/arithmetic-expansion.expect b/t/chainlint/arithmetic-expansion.expect
new file mode 100644
index 0000000000..09457d3196
--- /dev/null
+++ b/t/chainlint/arithmetic-expansion.expect
@@ -0,0 +1,9 @@
+(
+	foo &&
+	bar=$((42 + 1)) &&
+	baz
+>) &&
+(
+?!AMP?!	bar=$((42 + 1))
+	baz
+>)
diff --git a/t/chainlint/arithmetic-expansion.test b/t/chainlint/arithmetic-expansion.test
new file mode 100644
index 0000000000..16206960d8
--- /dev/null
+++ b/t/chainlint/arithmetic-expansion.test
@@ -0,0 +1,11 @@
+(
+	foo &&
+# LINT: closing ")" of $((...)) not misinterpreted as subshell-closing ")"
+	bar=$((42 + 1)) &&
+	baz
+) &&
+(
+# LINT: missing "&&" on $((...))
+	bar=$((42 + 1))
+	baz
+)
diff --git a/t/chainlint/broken-chain.expect b/t/chainlint/broken-chain.expect
new file mode 100644
index 0000000000..55b0f42a53
--- /dev/null
+++ b/t/chainlint/broken-chain.expect
@@ -0,0 +1,6 @@
+(
+	foo &&
+?!AMP?!	bar
+	baz &&
+	wop
+>)
diff --git a/t/chainlint/broken-chain.test b/t/chainlint/broken-chain.test
new file mode 100644
index 0000000000..3cc67b65d0
--- /dev/null
+++ b/t/chainlint/broken-chain.test
@@ -0,0 +1,8 @@
+(
+	foo &&
+# LINT: missing "&&" from 'bar'
+	bar
+	baz &&
+# LINT: final statement before closing ")" legitimately lacks "&&"
+	wop
+)
diff --git a/t/chainlint/close-subshell.expect b/t/chainlint/close-subshell.expect
new file mode 100644
index 0000000000..184688718a
--- /dev/null
+++ b/t/chainlint/close-subshell.expect
@@ -0,0 +1,25 @@
+(
+	foo
+>) &&
+(
+	bar
+>) >out &&
+(
+	baz
+>) 2>err &&
+(
+	boo
+>) <input &&
+(
+	bip
+>) | wuzzle &&
+(
+	bop
+>) | fazz 	fozz &&
+(
+	bup
+>) |
+fuzzle &&
+(
+	yop
+>)
diff --git a/t/chainlint/close-subshell.test b/t/chainlint/close-subshell.test
new file mode 100644
index 0000000000..508ca447fd
--- /dev/null
+++ b/t/chainlint/close-subshell.test
@@ -0,0 +1,27 @@
+# LINT: closing ")" with various decorations ("&&", ">", "|", etc.)
+(
+	foo
+) &&
+(
+	bar
+) >out &&
+(
+	baz
+) 2>err &&
+(
+	boo
+) <input &&
+(
+	bip
+) | wuzzle &&
+(
+	bop
+) | fazz \
+	fozz &&
+(
+	bup
+) |
+fuzzle &&
+(
+	yop
+)
diff --git a/t/chainlint/command-substitution.expect b/t/chainlint/command-substitution.expect
new file mode 100644
index 0000000000..ad4118e537
--- /dev/null
+++ b/t/chainlint/command-substitution.expect
@@ -0,0 +1,9 @@
+(
+	foo &&
+	bar=$(gobble) &&
+	baz
+>) &&
+(
+?!AMP?!	bar=$(gobble blocks)
+	baz
+>)
diff --git a/t/chainlint/command-substitution.test b/t/chainlint/command-substitution.test
new file mode 100644
index 0000000000..3bbb002a4c
--- /dev/null
+++ b/t/chainlint/command-substitution.test
@@ -0,0 +1,11 @@
+(
+	foo &&
+# LINT: closing ")" of $(...) not misinterpreted as subshell-closing ")"
+	bar=$(gobble) &&
+	baz
+) &&
+(
+# LINT: missing "&&" on $(...)
+	bar=$(gobble blocks)
+	baz
+)
diff --git a/t/chainlint/exit-subshell.expect b/t/chainlint/exit-subshell.expect
new file mode 100644
index 0000000000..bf78454f74
--- /dev/null
+++ b/t/chainlint/exit-subshell.expect
@@ -0,0 +1,5 @@
+(
+	foo || exit 1
+	bar &&
+	baz
+>)
diff --git a/t/chainlint/exit-subshell.test b/t/chainlint/exit-subshell.test
new file mode 100644
index 0000000000..4e6ab69b88
--- /dev/null
+++ b/t/chainlint/exit-subshell.test
@@ -0,0 +1,6 @@
+(
+# LINT: "|| exit {n}" valid subshell escape without hurting &&-chain
+	foo || exit 1
+	bar &&
+	baz
+)
diff --git a/t/chainlint/multi-line-string.expect b/t/chainlint/multi-line-string.expect
new file mode 100644
index 0000000000..8334c4cc8e
--- /dev/null
+++ b/t/chainlint/multi-line-string.expect
@@ -0,0 +1,9 @@
+(
+	x=line 1		line 2		line 3" &&
+?!AMP?!	y=line 1		line2'
+	foobar
+>) &&
+(
+	echo "there's nothing to see here" &&
+	exit
+>)
diff --git a/t/chainlint/multi-line-string.test b/t/chainlint/multi-line-string.test
new file mode 100644
index 0000000000..14cb44d51c
--- /dev/null
+++ b/t/chainlint/multi-line-string.test
@@ -0,0 +1,15 @@
+(
+	x="line 1
+		line 2
+		line 3" &&
+# LINT: missing "&&" on assignment
+	y='line 1
+		line2'
+	foobar
+) &&
+(
+# LINT: apostrophe (in a contraction) within string not misinterpreted as
+# LINT: starting multi-line single-quoted string
+	echo "there's nothing to see here" &&
+	exit
+)
diff --git a/t/chainlint/pipe.expect b/t/chainlint/pipe.expect
new file mode 100644
index 0000000000..211b901dbc
--- /dev/null
+++ b/t/chainlint/pipe.expect
@@ -0,0 +1,8 @@
+(
+	foo |
+	bar |
+	baz &&
+	fish |
+?!AMP?!	cow
+	sunder
+>)
diff --git a/t/chainlint/pipe.test b/t/chainlint/pipe.test
new file mode 100644
index 0000000000..e6af4de916
--- /dev/null
+++ b/t/chainlint/pipe.test
@@ -0,0 +1,12 @@
+(
+# LINT: no "&&" needed on line ending with "|"
+	foo |
+	bar |
+	baz &&
+
+# LINT: final line of pipe sequence ('cow') lacking "&&"
+	fish |
+	cow
+
+	sunder
+)
diff --git a/t/chainlint/semicolon.expect b/t/chainlint/semicolon.expect
new file mode 100644
index 0000000000..1d79384606
--- /dev/null
+++ b/t/chainlint/semicolon.expect
@@ -0,0 +1,20 @@
+(
+?!AMP?!?!SEMI?!	cat foo ; echo bar
+?!SEMI?!	cat foo ; echo bar
+>) &&
+(
+?!SEMI?!	cat foo ; echo bar &&
+?!SEMI?!	cat foo ; echo bar
+>) &&
+(
+	echo "foo; bar" &&
+?!SEMI?!	cat foo; echo bar
+>) &&
+(
+?!SEMI?!	foo;
+>) &&
+(
+cd foo &&
+	for i in a b c; do
+?!SEMI?!		echo;
+>	done)
diff --git a/t/chainlint/semicolon.test b/t/chainlint/semicolon.test
new file mode 100644
index 0000000000..d82c8ebbc0
--- /dev/null
+++ b/t/chainlint/semicolon.test
@@ -0,0 +1,25 @@
+(
+# LINT: missing internal "&&" and ending "&&"
+	cat foo ; echo bar
+# LINT: final statement before ")" only missing internal "&&"
+	cat foo ; echo bar
+) &&
+(
+# LINT: missing internal "&&"
+	cat foo ; echo bar &&
+	cat foo ; echo bar
+) &&
+(
+# LINT: not fooled by semicolon in string
+	echo "foo; bar" &&
+	cat foo; echo bar
+) &&
+(
+# LINT: unnecessary terminating semicolon
+	foo;
+) &&
+(cd foo &&
+	for i in a b c; do
+# LINT: unnecessary terminating semicolon
+		echo;
+	done)