Use a new, stricter format for the spec tests (#156)

- Test metadata always begins with `##`, which makes it less likely for us to confuse them with real comments.
- Test headers begin with `####` for aesthetics`.

Fixes issue #143.

Also:

- Update alias spec test so it's less likely to conflict with commands in $PATH (address issue #22)

spec/alias.test.sh

@@ -6,7 +6,7 @@
#
# Bash is the only one that doesn't support aliases!

### basic alias
#### basic alias
shopt -s expand_aliases  # bash requires this
alias hi='echo hello world'
hi
@@ -16,7 +16,7 @@ hello world
hi
## END

### alias with trailing space causes second alias expansion
#### alias with trailing space causes second alias expansion
shopt -s expand_aliases  # bash requires this

alias hi='echo hello world '
@@ -33,7 +33,7 @@ hello world !!!
hello world punct
## END

### iterative alias expansion of first word
#### iterative alias expansion of first word
shopt -s expand_aliases  # bash requires this
alias hi='echo hello world'
alias echo='echo --; echo '
@@ -44,7 +44,7 @@ hello world
## END


### expansion of alias with value
#### expansion of alias with value
shopt -s expand_aliases  # bash requires this
x=x
alias echo-x='echo $x'  # nothing is evaluated here
@@ -55,7 +55,7 @@ y hi
## END


### first and second word are the same
#### first and second word are the same
shopt -s expand_aliases  # bash requires this
x=x
alias echo-x='echo $x'  # nothing is evaluated here
@@ -67,7 +67,7 @@ x echo-x
x echo x
## END

### first and second word are the same with trailing space
#### first and second word are the same with trailing space
shopt -s expand_aliases  # bash requires this
x=x
alias echo-x='echo $x '  # nothing is evaluated here
@@ -76,7 +76,7 @@ echo-x echo-x
x echo x
## END

### defining multiple aliases, then unalias
#### defining multiple aliases, then unalias
shopt -s expand_aliases  # bash requires this
x=x
y=y
@@ -94,22 +94,22 @@ undefined
## END


### Invalid syntax of alias
#### Invalid syntax of alias
shopt -s expand_aliases  # bash requires this
alias e= 'echo --; echo'  # bad space here
e x
alias echo_alias_= 'echo --; echo'  # bad space here
echo_alias_ x
## status: 127

### Dynamic alias definition
#### Dynamic alias definition
shopt -s expand_aliases  # bash requires this
x=x
name='e'
name='echo_alias_'
val='=echo'
alias "$name$val"
e X
echo_alias_ X
## stdout: X

### Alias detection happens before expansion
#### Alias detection happens before expansion
shopt -s expand_aliases  # bash requires this
alias echo_alias_='echo'
cmd=echo_alias_
@@ -121,7 +121,7 @@ X
status=127
## END

### Alias name with punctuation
#### Alias name with punctuation
# NOTE: / is not OK in bash, but OK in other shells.  Must less restrictive
# than var names.
shopt -s expand_aliases  # bash requires this

spec/append.test.sh

@@ -1,68 +1,68 @@
#!/usr/bin/env bash

### Append string to string
#### Append string to string
s='abc'
s+=d
echo $s
# stdout: abcd
## stdout: abcd

### Append array to array
#### Append array to array
a=(x y )
a+=(t 'u v')
argv.py "${a[@]}"
# stdout: ['x', 'y', 't', 'u v']
## stdout: ['x', 'y', 't', 'u v']

### Append array to string should be an error
#### Append array to string should be an error
s='abc'
s+=(d e f)
echo $s
# BUG bash/mksh stdout: abc
# BUG bash/mksh status: 0
# status: 1
## BUG bash/mksh stdout: abc
## BUG bash/mksh status: 0
## status: 1

### Append string to array should be disallowed
#### Append string to array should be disallowed
# They treat this as implicit index 0.  We disallow this on the LHS, so we will
# also disallow it on the RHS.
a=(x y )
a+=z
argv.py "${a[@]}"
# OK bash/mksh stdout: ['xz', 'y']
# OK bash/mksh status: 0
# status: 1
## OK bash/mksh stdout: ['xz', 'y']
## OK bash/mksh status: 0
## status: 1

### Append string to array element
#### Append string to array element
# They treat this as implicit index 0.  We disallow this on the LHS, so we will
# also disallow it on the RHS.
a=(x y )
a[1]+=z
argv.py "${a[@]}"
# stdout: ['x', 'yz']
# status: 0
## stdout: ['x', 'yz']
## status: 0

### Append to last element
#### Append to last element
# Works in bash, but not mksh.  It seems like bash is doing the right thing.
# a[-1] is allowed on the LHS.  mksh doesn't have negative indexing?
a=(1 '2 3')
a[-1]+=' 4'
argv.py "${a[@]}"
# stdout: ['1', '2 3 4']
# BUG mksh stdout: ['1', '2 3', ' 4']
## stdout: ['1', '2 3 4']
## BUG mksh stdout: ['1', '2 3', ' 4']

### Try to append list to element
#### Try to append list to element
# bash - cannot assign list to array number
# mksh - a[-1]+: is not an identifier
a=(1 '2 3')
a[-1]+=(4 5)
# status: 1
## status: 1

### Strings have value semantics, not reference semantics
#### Strings have value semantics, not reference semantics
s1='abc'
s2=$s1
s1+='d'
echo $s1 $s2
# stdout: abcd abc
## stdout: abcd abc

### Append to nonexistent string
#### Append to nonexistent string
f() {
  local a+=a
  echo $a
@@ -85,9 +85,9 @@ f() {
  #echo $e
}
f
# stdout-json: "a\nb\nc\nd\ne\n"
## stdout-json: "a\nb\nc\nd\ne\n"

### Append to nonexistent array
#### Append to nonexistent array
f() {
  # NOTE: mksh doesn't like a=() after keyword.  Doesn't allow local arrays!
  local x+=(a b)
@@ -100,16 +100,16 @@ f() {
  argv.py "${z[@]}"
}
f
# stdout-json: "['a', 'b']\n['c', 'd']\n['e', 'f']\n"
# N-I mksh stdout-json: ""
# N-I mksh status: 1
## stdout-json: "['a', 'b']\n['c', 'd']\n['e', 'f']\n"
## N-I mksh stdout-json: ""
## N-I mksh status: 1

### Append used like env prefix is a parse error
#### Append used like env prefix is a parse error
# This should be an error in other shells but it's not.
A=a
A+=a printenv.py A
# status: 2
# BUG bash stdout: aa
# BUG bash status: 0
# BUG mksh stdout: a
# BUG mksh status: 0
## status: 2
## BUG bash stdout: aa
## BUG bash status: 0
## BUG mksh stdout: a
## BUG mksh status: 0

spec/arith-context.test.sh

@@ -8,85 +8,85 @@
# ${a : 1+2 : 1+2}
# a[1 + 2]=foo

### Multiple right brackets inside expression
#### Multiple right brackets inside expression
a=(1 2 3)
echo ${a[a[0]]} ${a[a[a[0]]]}
# stdout: 2 3
# N-I zsh status: 0
# N-I zsh stdout-json: "\n"
## stdout: 2 3
## N-I zsh status: 0
## N-I zsh stdout-json: "\n"

### Slicing of string with constants
#### Slicing of string with constants
s='abcd'
echo ${s:0} ${s:0:4} ${s:1:1}
# stdout: abcd abcd b
## stdout: abcd abcd b

### Slicing of string with variables
#### Slicing of string with variables
s='abcd'
zero=0
one=1
echo ${s:$zero} ${s:$zero:4} ${s:$one:$one}
# stdout: abcd abcd b
## stdout: abcd abcd b

### Array index on LHS of assignment
#### Array index on LHS of assignment
a=(1 2 3)
zero=0
a[zero+5-4]=X
echo ${a[@]}
# stdout: 1 X 3
# OK zsh stdout: X 2 3
## stdout: 1 X 3
## OK zsh stdout: X 2 3

### Array index on LHS with spaces
#### Array index on LHS with spaces
# zsh fails to parse this  because of the spaces.
a=(1 2 3)
zero=0
a[zero + 5 - 4]=X
echo ${a[@]}
# stdout: 1 X 3
# BUG zsh stdout-json: ""
# BUG zsh status: 1
## stdout: 1 X 3
## BUG zsh stdout-json: ""
## BUG zsh status: 1

### Array index on LHS with indices
#### Array index on LHS with indices
a=(1 2 3)
a[a[1]]=X
echo ${a[@]}
# stdout: 1 2 X
# OK zsh stdout: X 2 3
## stdout: 1 2 X
## OK zsh stdout: X 2 3

### Slicing of string with expressions
#### Slicing of string with expressions
# mksh accepts ${s:0} and ${s:$zero} but not ${s:zero}
# zsh says unrecognized modifier 'z'
s='abcd'
zero=0
echo ${s:zero} ${s:zero+0} ${s:zero+1:zero+1}
# stdout: abcd abcd b
# BUG mksh stdout-json: ""
# BUG mksh status: 1
# BUG zsh stdout-json: ""
# BUG zsh status: 1
## stdout: abcd abcd b
## BUG mksh stdout-json: ""
## BUG mksh status: 1
## BUG zsh stdout-json: ""
## BUG zsh status: 1

### Ambiguous colon in slice
#### Ambiguous colon in slice
s='abcd'
echo $(( 0 < 1 ? 2 : 0 ))  # evalutes to 2
echo ${s: 0 < 1 ? 2 : 0 : 1}  # 2:1 -- TRICKY THREE COLONS
# stdout-json: "2\nc\n"
# BUG mksh stdout-json: "2\n"
# BUG mksh status: 1
# BUG zsh stdout-json: "2\n"
# BUG zsh status: 1
## stdout-json: "2\nc\n"
## BUG mksh stdout-json: "2\n"
## BUG mksh status: 1
## BUG zsh stdout-json: "2\n"
## BUG zsh status: 1

### Triple parens should be disambiguated
#### Triple parens should be disambiguated
# The first paren is part of the math, parens 2 and 3 are a single token ending
# arith sub.
((a=1 + (2*3)))
echo $a $((1 + (2*3)))
# stdout: 7 7
## stdout: 7 7

### Quadruple parens should be disambiguated
#### Quadruple parens should be disambiguated
((a=1 + (2 * (3+4))))
echo $a $((1 + (2 * (3+4))))
# stdout: 15 15
## stdout: 15 15

### Alternative $[] syntax
#### Alternative $[] syntax
echo $[1 + 2] "$[3 * 4]"
# stdout: 3 12
# N-I mksh stdout: $[1 + 2] $[3 * 4]
## stdout: 3 12
## N-I mksh stdout: $[1 + 2] $[3 * 4]