v0.15.0

• Add operator mutations.

  • #1523
    #1530
    Add arithmetic operator swap mutations (+ ↔ -, * ↔ /).
    Multiplication/division skips multiplicative identity operands.

  • #1532
    #1533
    Add % → / and ** → * mutations.

  • #1527
    Add == ↔ != swap mutation.

  • #1534
    Add logical operator swap mutations (and ↔ or, && ↔ ||).

  • #1535
    #1576
    Add compound assignment operator swap mutations
    (+= ↔ -=, *= ↔ /=, %= → /=, **= → *=,
    &= ↔ |= ↔ ^=, <<= ↔ >>=, &&= ↔ ||=).

• Add selector replacement mutations.

  Orthogonal replacements (circular swaps):

  • #1559 select/filter ↔ reject
  • #1560 any? ↔ none?
  • #1561 take ↔ drop
  • #1562 append/push ↔ prepend/unshift
  • #1563 positive? ↔ negative?
  • #1564 zero? ↔ nonzero?
  • #1565 count ↔ size/length
  • #1568 keys ↔ values
  • #1571 even? ↔ odd?, min ↔ max, min_by ↔ max_by
  • #1573 all? ↔ none?, floor ↔ ceil,
    start_with? ↔ end_with?, transform_keys ↔ transform_values, upcase ↔ downcase
  • #1576 pop ↔ shift, each_key ↔ each_value,
    assoc ↔ rassoc, succ ↔ pred, chars ↔ bytes, empty? ↔ any?,
    grep ↔ grep_v

  Semantic reductions:

  • #1542 Bang → non-bang methods
    (e.g. map! → map, sort! → sort, compact! → compact).
  • #1567
    #1572 Enumerable reductions
    (collect → each, each_with_object → each, each_with_index → each,
    each_cons → each, each_slice → each, sample → first/last,
    sort_by → sort).
  • #1574 filter_map → map,
    delete_if → reject, keep_if → select, collect_concat → collect,
    chunk/chunk_while/slice_before/slice_after/slice_when → each,
    strip → lstrip/rstrip, to_f → to_i,
    defined? → true, strip regexp m (multiline) flag.

• #1558
  #1537

  Add pattern-matching mutation support. Dedicated mutators for case/in expressions,
  in patterns, match alternatives (A | B), and pattern match predicates
  (x in pattern → false). Guard clauses in pattern matches are now mutated.

• #1555
  #1566

  Add control flow mutations. while ↔ until orthogonal swap mutations.
  while_post and until_post support for begin...end while/begin...end until
  constructs.

• #1539

  Add super ↔ super() mutation operators to test implicit vs explicit
  argument forwarding.

• #1536

  Add rescue clause removal mutations. When multiple rescue clauses exist,
  emit mutations that remove each clause individually.

• #1543

  Add inline rescue modifier mutations (foo rescue bar → bar).

• #1556

  Add explicit ensure mutator with ensure-clause reduction.

• #1526

  Add empty collection return value mutations (to_a → [], to_h → {},
  to_s → "").

• #1540

  Add type-aware default return mutations for method bodies
  (Array → [], Hash → {}, String → "", Integer → 0, Float → 0.0).

• #1544

  Add generic receiver promotion mutations for blocks (a.b { } → a).

• #1547

  Add non-empty string to empty string mutation.

• #1557

  Add literal mutators for complex and rational numeric nodes.

• #1553

  Add RSpec 4 support.

• Dependency updates:

  • #1570
    Bump parser dependency to ~> 3.3.10 and unparser dependency to ~> 0.8.2.

• #1550

  Fix bundler stability issue.

v0.14.2

What's Changed

• Fix coverage percentage rounding up to 100% when mutations survive by @sferik in #1512
• Change to allow builds by other peoples PRs by @mbj in #1513
• Add visual progress bar for TTY output by @sferik in #1514
• Add bitwise operator mutations by @sferik in #1516
• Change version to v0.14.2 by @mbj in #1517
• Add improved quick start documentation by @mbj in #1519
• Fix readme badge by @mbj in #1520

Full Changelog: v0.14.1...v0.14.2