expertiza/expertiza

This cop checks for uses of DateTime that should be replaced by Date or Time.

Example:

# bad - uses `DateTime` for current time
DateTime.now

# good - uses `Time` for current time
Time.now

# bad - uses `DateTime` for modern date
DateTime.iso8601('2016-06-29')

# good - uses `Date` for modern date
Date.iso8601('2016-06-29')

# good - uses `DateTime` with start argument for historical date
DateTime.iso8601('1751-04-23', Date::ENGLAND)

This cop checks that include, extend and prepend exists at the top level. Using these at the top level affects the behavior of Object. There will not be using include, extend and prepend at the top level. Let's use it inside class or module.

Example:

# bad
include M

class C
end

# bad
extend M

class C
end

# bad
prepend M

class C
end

# good
class C
  include M
end

# good
class C
  extend M
end

# good
class C
  prepend M
end

Checks that operators have space around them, except for ** which should not have surrounding space.

Example:

# bad
total = 3*4
"apple"+"juice"
my_number = 38/4
a ** b

# good
total = 3 * 4
"apple" + "juice"
my_number = 38 / 4
a**b

Checks that braces used for hash literals have or don't have surrounding space depending on configuration.

Example: EnforcedStyle: space

# The `space` style enforces that hash literals have
# surrounding space.

# bad
h = {a: 1, b: 2}

# good
h = { a: 1, b: 2 }

Example: EnforcedStyle: no_space

# The `no_space` style enforces that hash literals have
# no surrounding space.

# bad
h = { a: 1, b: 2 }

# good
h = {a: 1, b: 2}

Example: EnforcedStyle: compact

# The `compact` style normally requires a space inside
# hash braces, with the exception that successive left
# braces or right braces are collapsed together in nested hashes.

# bad
h = { a: { b: 2 } }

# good
h = { a: { b: 2 }}

Checks if uses of quotes match the configured preference.

Example: EnforcedStyle: single_quotes (default)

# bad
"No special symbols"
"No string interpolation"
"Just text"

# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"

Example: EnforcedStyle: double_quotes

# bad
'Just some text'
'No special chars or interpolation'

# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"

This cop checks for usage of comparison operators (==, >, <) to test numbers as zero, positive, or negative. These can be replaced by their respective predicate methods. The cop can also be configured to do the reverse.

The cop disregards #nonzero? as it its value is truthy or falsey, but not true and false, and thus not always interchangeable with != 0.

The cop ignores comparisons to global variables, since they are often populated with objects which can be compared with integers, but are not themselves Interger polymorphic.

Example: EnforcedStyle: predicate (default)

# bad

foo == 0
0 > foo
bar.baz > 0

# good

foo.zero?
foo.negative?
bar.baz.positive?

Example: EnforcedStyle: comparison

# bad

foo.zero?
foo.negative?
bar.baz.positive?

# good

foo == 0
0 > foo
bar.baz > 0