dbracket.test.sh

#!/usr/bin/env bash

#### [[ glob matching, [[ has no glob expansion
[[ foo.py == *.py ]] && echo true
[[ foo.p  == *.py ]] || echo false
## stdout-json: "true\nfalse\n"

#### [[ glob matching with escapes
[[ 'foo.*' == *."*" ]] && echo true
# note that the pattern arg to fnmatch should be '*.\*'
## stdout: true

#### equality
[[ '*.py' == '*.py' ]] && echo true
[[ foo.py == '*.py' ]] || echo false
## stdout-json: "true\nfalse\n"

#### [[ glob matching with unquoted var
pat=*.py
[[ foo.py == $pat ]] && echo true
[[ foo.p  == $pat ]] || echo false
## stdout-json: "true\nfalse\n"

#### [[ regex matching
# mksh doesn't have this syntax of regex matching.  I guess it comes from perl?
regex='.*\.py'
[[ foo.py =~ $regex ]] && echo true
[[ foo.p  =~ $regex ]] || echo false
## stdout-json: "true\nfalse\n"
## N-I mksh stdout-json: ""
## N-I mksh status: 1

#### [[ regex syntax error
# hm, it doesn't show any error, but it exits 2.
[[ foo.py =~ * ]] && echo true
## status: 2
## N-I mksh status: 1

#### [[ has no word splitting
var='one two'
[[ 'one two' == $var ]] && echo true
## stdout: true

#### [[ has quote joining
var='one two'
[[ 'one 'tw"o" == $var ]] && echo true
## stdout: true

#### [[ empty string is false
[[ 'a' ]] && echo true
[[ ''  ]] || echo false
## stdout-json: "true\nfalse\n"

#### && chain
[[ t && t && '' ]] || echo false
## stdout: false

#### || chain
[[ '' || '' || t ]] && echo true
## stdout: true

#### [[ compound expressions
# Notes on whitespace:
# - 1 and == need space seprating them, but ! and ( don't.
# - [[ needs whitesapce after it, but ]] doesn't need whitespace before it!
[[ ''||! (1 == 2)&&(2 == 2)]] && echo true
## stdout: true

# NOTE on the two cases below.  We're comparing
#   (a || b) && c   vs.   a || (b && c)
#
# a = true, b = false, c = false is an example where they are different.
# && and || have precedence inside

#### precedence of && and || inside [[
[[ True || '' && '' ]] && echo true
## stdout: true

#### precedence of && and || in a command context
if test True || test '' && test ''; then
  echo YES
else
  echo "NO precedence"
fi
## stdout: NO precedence

# http://tldp.org/LDP/abs/html/testconstructs.html#DBLBRACKETS

#### Octal literals with -eq
shopt -u strict-arith || true
decimal=15
octal=017   # = 15 (decimal)
[[ $decimal -eq $octal ]] && echo true
[[ $decimal -eq ZZZ$octal ]] || echo false
## STDOUT:
true
false
## END
## N-I mksh stdout: false
# mksh doesn't implement this syntax for literals.

#### Hex literals with -eq
shopt -u strict-arith || true
decimal=15
hex=0x0f    # = 15 (decimal)
[[ $decimal -eq $hex ]] && echo true
[[ $decimal -eq ZZZ$hex ]] || echo false
## stdout-json: "true\nfalse\n"
## N-I mksh stdout: false

# TODO: Add tests for this
# https://www.gnu.org/software/bash/manual/bash.html#Bash-Conditional-Expressions
# When used with [[, the ‘<’ and ‘>’ operators sort lexicographically using the
# current locale. The test command uses ASCII ordering.

#### > on strings
# NOTE: < doesn't need space, even though == does?  That's silly.
[[ b>a ]] && echo true
[[ b<a ]] || echo false
## stdout-json: "true\nfalse\n"

#### != on strings
# NOTE: b!=a does NOT work
[[ b != a ]] && echo true
[[ a != a ]] || echo false
## stdout-json: "true\nfalse\n"

#### -eq on strings 
# This is lame behavior: it does a conversion to 0 first for any string
shopt -u strict-arith || true
[[ a -eq a ]] && echo true
[[ a -eq b ]] && echo true
## STDOUT: 
true
true
## END

#### [[ compare with literal -f (compare with test-builtin.test.sh)
var=-f
[[ $var == -f ]] && echo true
[[ '-f' == $var ]] && echo true
## stdout-json: "true\ntrue\n"

#### [[ with op variable (compare with test-builtin.test.sh)
# Parse error -- parsed BEFORE evaluation of vars
op='=='
[[ a $op a ]] && echo true
[[ a $op b ]] || echo false
## status: 2
## OK mksh status: 1

#### [[ with unquoted empty var (compare with test-builtin.test.sh)
empty=''
[[ $empty == '' ]] && echo true
## stdout: true

#### [[ at runtime doesn't work
dbracket=[[
$dbracket foo == foo ]]
## status: 127

#### [[ with env prefix doesn't work
FOO=bar [[ foo == foo ]]
## status: 127

#### [[ over multiple lines is OK
# Hm it seems you can't split anywhere?
[[ foo == foo
&& bar == bar
]] && echo true
## status: 0
## STDOUT:
true
## END

#### Argument that looks like a command word operator
[[ -f -f ]] || echo false
[[ -f == ]] || echo false
## STDOUT:
false
false
## END

#### Argument that looks like a real operator
[[ -f < ]] && echo 'should be parse error'
## status: 2
## OK mksh status: 1

#### User array compared to "$@" (broken unless shopt -s strict-array)
# Both are coerced to string!  It treats it more like an  UNQUOTED ${a[@]}.

a=('1 3' 5)
b=(1 2 3)
set -- 1 '3 5'
[[ "$@" = "${a[@]}" ]] && echo true
[[ "$@" = "${b[@]}" ]] || echo false
## STDOUT:
true
false
## END

#### Array coerces to string (shopt -s strict-array to disallow)
a=('1 3' 5)
[[ '1 3 5' = "${a[@]}" ]] && echo true
[[ '1 3 4' = "${a[@]}" ]] || echo false
## STDOUT:
true
false
## END

#### (( array1 == array2 )) doesn't work
a=('1 3' 5)
b=('1 3' 5)
c=('1' '3 5')
d=('1' '3 6')

# shells EXPAND a and b first
(( a == b ))
echo status=$?

(( a == c ))
echo status=$?

(( a == d ))
echo status=$?

## stdout-json: ""
## status: 1
## BUG bash STDOUT:
status=1
status=1
status=1
## END
## BUG bash status: 0

#### Quotes don't matter in comparison
[[ '3' = 3 ]] && echo true
[[ '3' -eq 3 ]] && echo true
## STDOUT:
true
true
## END

#### -eq does dynamic arithmetic parsing (not supported in OSH)
[[ 1+2 -eq 3 ]] && echo true
expr='1+2'
[[ $expr -eq 3 ]] && echo true  # must be dynamically parsed
## STDOUT:
true
true
## END
## N-I osh stdout-json: ""
## N-I osh status: 1

#### -eq coercion produces weird results
shopt -u strict-arith || true
[[ '' -eq 0 ]] && echo true
## stdout: true

#### [[ '(' ]] is treated as literal
[[ '(' ]]
echo status=$?
## stdout: status=0

#### [[ '(' foo ]] is syntax error
[[ '(' foo ]]
echo status=$?
## status: 2
## OK mksh status: 1

#### empty ! is treated as literal
[[ '!' ]]
echo status=$?
## stdout: status=0

#### [[ -z ]] is syntax error
[[ -z ]]
echo status=$?
## status: 2
## OK mksh status: 1

#### [[ -z '>' ]]
[[ -z '>' ]] || echo false  # -z is operator
## stdout: false

#### [[ -z '>' a ]] is syntax error
[[ -z '>' -- ]]
echo status=$?
## status: 2
## OK mksh status: 1

#### test whether ']]' is empty
[[ ']]' ]]
echo status=$?
## status: 0

#### [[ ]] is syntax error
[[ ]]
echo status=$?
## stdout-json: ""
## status: 2
## OK mksh status: 1

#### [[ && ]] is syntax error
[[ && ]]
echo status=$?
## stdout-json: ""
## status: 2
## OK mksh status: 1