From 117653ee12b38e1328eccbf2a252911f118db01b Mon Sep 17 00:00:00 2001
From: Daniel Mita <966706+m-dango@users.noreply.github.com>
Date: Wed, 16 Jun 2021 12:18:07 +0100
Subject: [PATCH] Add strain to generator (#417)

---
 exercises/practice/binary/Binary.pm           | 18 ++++
 exercises/practice/etl/.meta/config.json      |  4 +-
 exercises/practice/hexadecimal/Hexadecimal.pm | 18 ++++
 .../practice/linked-list/.meta/config.json    |  6 +-
 exercises/practice/linked-list/Deque.pm       | 46 +++++++++
 exercises/practice/list-ops/ListOps.pm        | 24 +++++
 .../practice/ocr-numbers/.meta/config.json    |  4 +-
 .../palindrome-products/.meta/config.json     |  6 +-
 .../palindrome-products/Palindrome.pm         | 24 +++++
 .../point-mutations/.meta/config.json         |  6 +-
 exercises/practice/point-mutations/DNA.pm     | 18 ++++
 .../practice/prime-factors/.meta/config.json  |  6 +-
 exercises/practice/prime-factors/Prime.pm     | 12 +++
 exercises/practice/proverb/Proverb.pm         | 12 +++
 .../pythagorean-triplet/.meta/config.json     |  6 +-
 .../practice/pythagorean-triplet/Triplet.pm   | 36 +++++++
 .../practice/queen-attack/.meta/config.json   |  6 +-
 exercises/practice/queen-attack/Queens.pm     | 36 +++++++
 .../rna-transcription/.meta/config.json       |  4 +-
 .../robot-simulator/.meta/config.json         |  6 +-
 exercises/practice/robot-simulator/Robot.pm   | 82 ++++++++++++++++
 .../practice/saddle-points/.meta/config.json  |  6 +-
 exercises/practice/saddle-points/Matrix.pm    | 30 ++++++
 .../practice/simple-cipher/.meta/config.json  |  6 +-
 exercises/practice/simple-cipher/Cipher.pm    | 24 +++++
 .../simple-linked-list/.meta/config.json      |  6 +-
 .../practice/simple-linked-list/LinkedList.pm | 31 +++++++
 .../practice/strain/.meta/exercise-data.yaml  | 93 +++++++++++++++++++
 .../practice/strain/.meta/solutions/Strain.pm |  3 +-
 exercises/practice/strain/Strain.pm           | 17 ++++
 exercises/practice/strain/strain.t            | 48 ++++------
 exercises/practice/trinary/Trinary.pm         | 17 ++++
 32 files changed, 592 insertions(+), 69 deletions(-)
 create mode 100644 exercises/practice/binary/Binary.pm
 create mode 100644 exercises/practice/hexadecimal/Hexadecimal.pm
 create mode 100644 exercises/practice/linked-list/Deque.pm
 create mode 100644 exercises/practice/list-ops/ListOps.pm
 create mode 100644 exercises/practice/palindrome-products/Palindrome.pm
 create mode 100644 exercises/practice/point-mutations/DNA.pm
 create mode 100644 exercises/practice/prime-factors/Prime.pm
 create mode 100644 exercises/practice/proverb/Proverb.pm
 create mode 100644 exercises/practice/pythagorean-triplet/Triplet.pm
 create mode 100644 exercises/practice/queen-attack/Queens.pm
 create mode 100644 exercises/practice/robot-simulator/Robot.pm
 create mode 100644 exercises/practice/saddle-points/Matrix.pm
 create mode 100644 exercises/practice/simple-cipher/Cipher.pm
 create mode 100644 exercises/practice/simple-linked-list/LinkedList.pm
 create mode 100644 exercises/practice/strain/.meta/exercise-data.yaml
 create mode 100644 exercises/practice/strain/Strain.pm
 mode change 100644 => 100755 exercises/practice/strain/strain.t
 create mode 100644 exercises/practice/trinary/Trinary.pm

diff --git a/exercises/practice/binary/Binary.pm b/exercises/practice/binary/Binary.pm
new file mode 100644
index 00000000..f3e8dfc2
--- /dev/null
+++ b/exercises/practice/binary/Binary.pm
@@ -0,0 +1,18 @@
+package Binary;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $binary ) = @_;
+  
+  return undef;
+}
+
+sub to_decimal {
+  my $self = shift;
+
+  return undef;
+}
+
+__PACKAGE__;
diff --git a/exercises/practice/etl/.meta/config.json b/exercises/practice/etl/.meta/config.json
index 764bf88c..843a4c3b 100644
--- a/exercises/practice/etl/.meta/config.json
+++ b/exercises/practice/etl/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "Etl.pm"
+      "ETL.pm"
     ],
     "test": [
       "etl.t"
     ],
     "example": [
-      ".meta/solutions/Etl.pm"
+      ".meta/solutions/ETL.pm"
     ]
   },
   "source": "The Jumpstart Lab team",
diff --git a/exercises/practice/hexadecimal/Hexadecimal.pm b/exercises/practice/hexadecimal/Hexadecimal.pm
new file mode 100644
index 00000000..30db01de
--- /dev/null
+++ b/exercises/practice/hexadecimal/Hexadecimal.pm
@@ -0,0 +1,18 @@
+package Hexadecimal;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $hexadecimal ) = @_;
+  
+  return undef;
+}
+
+sub to_decimal {
+  my $self = shift;
+
+  return undef;
+}
+
+__PACKAGE__;
diff --git a/exercises/practice/linked-list/.meta/config.json b/exercises/practice/linked-list/.meta/config.json
index da3e9c39..4a42e82c 100644
--- a/exercises/practice/linked-list/.meta/config.json
+++ b/exercises/practice/linked-list/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "LinkedList.pm"
+      "Deque.pm"
     ],
     "test": [
-      "linked-list.t"
+      "deque.t"
     ],
     "example": [
-      ".meta/solutions/LinkedList.pm"
+      ".meta/solutions/Deque.pm"
     ]
   },
   "source": "Classic computer science topic"
diff --git a/exercises/practice/linked-list/Deque.pm b/exercises/practice/linked-list/Deque.pm
new file mode 100644
index 00000000..df5eecf7
--- /dev/null
+++ b/exercises/practice/linked-list/Deque.pm
@@ -0,0 +1,46 @@
+package Deque;
+use strict;
+use warnings;
+
+sub new {
+  my ($class) = @_;
+  
+  return undef;
+}
+
+sub push {
+  my ( $self, $value ) = @_;
+
+  return undef;
+}
+
+sub pop {
+  my ($self) = @_;
+
+  return undef;
+}
+
+sub shift {
+  my ($self) = @_;
+
+  return undef;
+}
+
+sub unshift {
+  my ( $self, $value ) = @_;
+
+  return undef;
+}
+
+package Element;
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, %data ) = @_;
+  
+  return undef;
+}
+
+1;
+
diff --git a/exercises/practice/list-ops/ListOps.pm b/exercises/practice/list-ops/ListOps.pm
new file mode 100644
index 00000000..27c35d5c
--- /dev/null
+++ b/exercises/practice/list-ops/ListOps.pm
@@ -0,0 +1,24 @@
+package ListOps;
+
+use strict;
+use warnings;
+
+sub map {
+  my ( $func, $list ) = @_;
+
+  return undef;
+}
+
+sub reduce {
+  my ( $func, $list ) = @_;
+
+  return undef;
+}
+
+sub length {
+  my $list = shift;
+
+  return undef;
+}
+
+1;
diff --git a/exercises/practice/ocr-numbers/.meta/config.json b/exercises/practice/ocr-numbers/.meta/config.json
index 3a7e468b..4466a598 100644
--- a/exercises/practice/ocr-numbers/.meta/config.json
+++ b/exercises/practice/ocr-numbers/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "OcrNumbers.pm"
+      "OCRNumbers.pm"
     ],
     "test": [
       "ocr-numbers.t"
     ],
     "example": [
-      ".meta/solutions/OcrNumbers.pm"
+      ".meta/solutions/OCRNumbers.pm"
     ]
   },
   "source": "Inspired by the Bank OCR kata",
diff --git a/exercises/practice/palindrome-products/.meta/config.json b/exercises/practice/palindrome-products/.meta/config.json
index ed04f685..291aa63e 100644
--- a/exercises/practice/palindrome-products/.meta/config.json
+++ b/exercises/practice/palindrome-products/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "PalindromeProducts.pm"
+      "Palindrome.pm"
     ],
     "test": [
-      "palindrome-products.t"
+      "palindrome.t"
     ],
     "example": [
-      ".meta/solutions/PalindromeProducts.pm"
+      ".meta/solutions/Palindrome.pm"
     ]
   },
   "source": "Problem 4 at Project Euler",
diff --git a/exercises/practice/palindrome-products/Palindrome.pm b/exercises/practice/palindrome-products/Palindrome.pm
new file mode 100644
index 00000000..dd158e22
--- /dev/null
+++ b/exercises/practice/palindrome-products/Palindrome.pm
@@ -0,0 +1,24 @@
+package Palindrome;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $min_max ) = @_;
+  
+  return undef;
+}
+
+sub largest {
+  my $self = shift;
+  
+  return undef;
+}
+
+sub smallest {
+  my $self = shift;
+  
+  return undef;
+}
+
+1;
diff --git a/exercises/practice/point-mutations/.meta/config.json b/exercises/practice/point-mutations/.meta/config.json
index 09549481..ea852a63 100644
--- a/exercises/practice/point-mutations/.meta/config.json
+++ b/exercises/practice/point-mutations/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "PointMutations.pm"
+      "DNA.pm"
     ],
     "test": [
-      "point-mutations.t"
+      "dna.t"
     ],
     "example": [
-      ".meta/solutions/PointMutations.pm"
+      ".meta/solutions/DNA.pm"
     ]
   },
   "source": "The Calculating Point Mutations problem at Rosalind",
diff --git a/exercises/practice/point-mutations/DNA.pm b/exercises/practice/point-mutations/DNA.pm
new file mode 100644
index 00000000..1d03e1a8
--- /dev/null
+++ b/exercises/practice/point-mutations/DNA.pm
@@ -0,0 +1,18 @@
+package DNA;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $strand ) = @_;
+  
+  return undef;
+}
+
+sub hamming_distance {
+  my ( $self, $strand ) = @_;
+  
+  return undef;
+}
+
+__PACKAGE__;
diff --git a/exercises/practice/prime-factors/.meta/config.json b/exercises/practice/prime-factors/.meta/config.json
index e460c5e4..6d7185ba 100644
--- a/exercises/practice/prime-factors/.meta/config.json
+++ b/exercises/practice/prime-factors/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "PrimeFactors.pm"
+      "Prime.pm"
     ],
     "test": [
-      "prime-factors.t"
+      "prime.t"
     ],
     "example": [
-      ".meta/solutions/PrimeFactors.pm"
+      ".meta/solutions/Prime.pm"
     ]
   },
   "source": "The Prime Factors Kata by Uncle Bob",
diff --git a/exercises/practice/prime-factors/Prime.pm b/exercises/practice/prime-factors/Prime.pm
new file mode 100644
index 00000000..b280817e
--- /dev/null
+++ b/exercises/practice/prime-factors/Prime.pm
@@ -0,0 +1,12 @@
+package Prime;
+use strict;
+use warnings;
+
+sub factors {
+  my ($num) = @_;
+
+  return undef;
+}
+
+1;
+
diff --git a/exercises/practice/proverb/Proverb.pm b/exercises/practice/proverb/Proverb.pm
new file mode 100644
index 00000000..3ccb7731
--- /dev/null
+++ b/exercises/practice/proverb/Proverb.pm
@@ -0,0 +1,12 @@
+package Proverb;
+
+use strict;
+use warnings;
+
+sub proverb {
+  my ( $items, $qualifier ) = @_;
+  
+  return undef;
+}
+
+__PACKAGE__;
diff --git a/exercises/practice/pythagorean-triplet/.meta/config.json b/exercises/practice/pythagorean-triplet/.meta/config.json
index e65b84c3..5015e832 100644
--- a/exercises/practice/pythagorean-triplet/.meta/config.json
+++ b/exercises/practice/pythagorean-triplet/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "PythagoreanTriplet.pm"
+      "Triplet.pm"
     ],
     "test": [
-      "pythagorean-triplet.t"
+      "triplet.t"
     ],
     "example": [
-      ".meta/solutions/PythagoreanTriplet.pm"
+      ".meta/solutions/Triplet.pm"
     ]
   },
   "source": "Problem 9 at Project Euler",
diff --git a/exercises/practice/pythagorean-triplet/Triplet.pm b/exercises/practice/pythagorean-triplet/Triplet.pm
new file mode 100644
index 00000000..4e90a421
--- /dev/null
+++ b/exercises/practice/pythagorean-triplet/Triplet.pm
@@ -0,0 +1,36 @@
+package Triplet;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, @args ) = @_;
+
+  return undef;
+}
+
+sub is_pythagorean {
+  my $self = shift;
+  
+  return undef;
+}
+
+sub sum {
+  my $self = shift;
+  
+  return undef;
+}
+
+sub product {
+  my $self = shift;
+
+  return undef;
+}
+
+sub products {
+  my $self = shift;
+
+  return undef;
+}
+
+1;
diff --git a/exercises/practice/queen-attack/.meta/config.json b/exercises/practice/queen-attack/.meta/config.json
index ff27c64a..ef8fe50e 100644
--- a/exercises/practice/queen-attack/.meta/config.json
+++ b/exercises/practice/queen-attack/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "QueenAttack.pm"
+      "Queens.pm"
     ],
     "test": [
-      "queen-attack.t"
+      "queen.t"
     ],
     "example": [
-      ".meta/solutions/QueenAttack.pm"
+      ".meta/solutions/Queens.pm"
     ]
   },
   "source": "J Dalbey's Programming Practice problems",
diff --git a/exercises/practice/queen-attack/Queens.pm b/exercises/practice/queen-attack/Queens.pm
new file mode 100644
index 00000000..0324901e
--- /dev/null
+++ b/exercises/practice/queen-attack/Queens.pm
@@ -0,0 +1,36 @@
+package Queens;
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, %data ) = @_;
+
+  return undef;
+}
+
+sub white {
+  my ($self) = @_;
+  
+  return undef;
+}
+
+sub black {
+  my ($self) = @_;
+  
+  return undef;
+}
+
+sub to_string {
+  my ($self) = @_;
+  
+  return undef;
+}
+
+sub can_attack {
+  my ($self) = @_;
+
+  return undef;
+}
+
+1;
+
diff --git a/exercises/practice/rna-transcription/.meta/config.json b/exercises/practice/rna-transcription/.meta/config.json
index 3994f036..67ef35be 100644
--- a/exercises/practice/rna-transcription/.meta/config.json
+++ b/exercises/practice/rna-transcription/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "RnaTranscription.pm"
+      "RNA.pm"
     ],
     "test": [
       "rna-transcription.t"
     ],
     "example": [
-      ".meta/solutions/RnaTranscription.pm"
+      ".meta/solutions/RNA.pm"
     ]
   },
   "source": "Hyperphysics",
diff --git a/exercises/practice/robot-simulator/.meta/config.json b/exercises/practice/robot-simulator/.meta/config.json
index e1836a8d..8a4b3ce1 100644
--- a/exercises/practice/robot-simulator/.meta/config.json
+++ b/exercises/practice/robot-simulator/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "RobotSimulator.pm"
+      "Robot.pm"
     ],
     "test": [
-      "robot-simulator.t"
+      "robot_simulator.t"
     ],
     "example": [
-      ".meta/solutions/RobotSimulator.pm"
+      ".meta/solutions/Robot.pm"
     ]
   },
   "source": "Inspired by an interview question at a famous company.",
diff --git a/exercises/practice/robot-simulator/Robot.pm b/exercises/practice/robot-simulator/Robot.pm
new file mode 100644
index 00000000..68c79c1f
--- /dev/null
+++ b/exercises/practice/robot-simulator/Robot.pm
@@ -0,0 +1,82 @@
+# there are 2 packages in this file; separate them once multiple files are supported
+
+use strict;
+use warnings;
+
+{
+
+  package Robot;
+
+  
+  sub new { 
+    return undef;
+  }
+
+  sub bearing { 
+    return undef;
+  }
+
+  sub coordinates { 
+    return undef;
+  }
+
+  sub orient {
+    my ( $self, $direction ) = @_;
+    
+    return undef;
+  }
+
+  sub turn_right {
+    my $self = shift;
+
+    return undef;
+  }
+
+  sub turn_left {
+    my $self = shift;
+
+    return undef;
+  }
+
+  sub at {
+    my ( $self, $x, $y ) = @_;
+    
+    return undef;
+  }
+
+  sub advance {
+    my $self = shift;
+    
+    return undef;
+  }
+
+}    # end of Package Example;
+
+{
+
+  package Simulator;
+
+  sub new { 
+    return undef;
+  }
+
+  sub place {
+    my ( $self, $robot, $options ) = @_;
+    
+    return undef;
+  }
+
+  sub evaluate {
+    my ( $self, $robot, $abbreviation ) = @_;
+    
+    return undef;
+  }
+
+  sub instructions {
+    my ( $self, $abbreviation ) = @_;
+    
+    return undef;
+  }
+}
+
+1;
diff --git a/exercises/practice/saddle-points/.meta/config.json b/exercises/practice/saddle-points/.meta/config.json
index a412255a..8ac75040 100644
--- a/exercises/practice/saddle-points/.meta/config.json
+++ b/exercises/practice/saddle-points/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "SaddlePoints.pm"
+      "Matrix.pm"
     ],
     "test": [
-      "saddle-points.t"
+      "saddle_points.t"
     ],
     "example": [
-      ".meta/solutions/SaddlePoints.pm"
+      ".meta/solutions/Matrix.pm"
     ]
   },
   "source": "J Dalbey's Programming Practice problems",
diff --git a/exercises/practice/saddle-points/Matrix.pm b/exercises/practice/saddle-points/Matrix.pm
new file mode 100644
index 00000000..79751328
--- /dev/null
+++ b/exercises/practice/saddle-points/Matrix.pm
@@ -0,0 +1,30 @@
+package Matrix;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $matrix_str ) = @_;
+  
+  return undef;
+}
+
+sub rows {
+  my ( $self, $index ) = @_;
+  
+  return undef;
+}
+
+sub columns {
+  my ( $self, $index ) = @_;
+  
+  return undef;
+}
+
+sub saddle_points {
+  my $self = shift;
+  
+  return undef;
+}
+
+1;
diff --git a/exercises/practice/simple-cipher/.meta/config.json b/exercises/practice/simple-cipher/.meta/config.json
index 6573da13..2571b062 100644
--- a/exercises/practice/simple-cipher/.meta/config.json
+++ b/exercises/practice/simple-cipher/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "SimpleCipher.pm"
+      "Cipher.pm"
     ],
     "test": [
-      "simple-cipher.t"
+      "cipher.t"
     ],
     "example": [
-      ".meta/solutions/SimpleCipher.pm"
+      ".meta/solutions/Cipher.pm"
     ]
   },
   "source": "Substitution Cipher at Wikipedia",
diff --git a/exercises/practice/simple-cipher/Cipher.pm b/exercises/practice/simple-cipher/Cipher.pm
new file mode 100644
index 00000000..bfd45844
--- /dev/null
+++ b/exercises/practice/simple-cipher/Cipher.pm
@@ -0,0 +1,24 @@
+package Cipher;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $key ) = @_;
+
+  return undef;
+}
+
+sub encode {
+  my ( $self, $plaintext ) = @_;
+  
+  return undef;
+}
+
+sub decode {
+  my ( $self, $cipher ) = @_;
+  
+  return undef;
+}
+
+1;
diff --git a/exercises/practice/simple-linked-list/.meta/config.json b/exercises/practice/simple-linked-list/.meta/config.json
index c7d3578a..0b41b102 100644
--- a/exercises/practice/simple-linked-list/.meta/config.json
+++ b/exercises/practice/simple-linked-list/.meta/config.json
@@ -3,13 +3,13 @@
   "authors": [],
   "files": {
     "solution": [
-      "SimpleLinkedList.pm"
+      "LinkedList.pm"
     ],
     "test": [
-      "simple-linked-list.t"
+      "simple_linked_list.t"
     ],
     "example": [
-      ".meta/solutions/SimpleLinkedList.pm"
+      ".meta/solutions/LinkedList.pm"
     ]
   },
   "source": "Inspired by 'Data Structures and Algorithms with Object-Oriented Design Patterns in Ruby', singly linked-lists.",
diff --git a/exercises/practice/simple-linked-list/LinkedList.pm b/exercises/practice/simple-linked-list/LinkedList.pm
new file mode 100644
index 00000000..88ddc96e
--- /dev/null
+++ b/exercises/practice/simple-linked-list/LinkedList.pm
@@ -0,0 +1,31 @@
+package LinkedList;
+
+use strict;
+use warnings;
+
+sub new {
+  my $class = shift;
+  
+  return undef;
+}
+
+sub from_array {
+  my ( $pkg, $array ) = @_;
+
+  return undef;
+}
+
+sub to_array {
+  my $self = shift;
+
+  return undef;
+}
+
+sub reverse : method {
+  my $self = shift;
+
+  return undef;
+}
+
+1;
+
diff --git a/exercises/practice/strain/.meta/exercise-data.yaml b/exercises/practice/strain/.meta/exercise-data.yaml
new file mode 100644
index 00000000..ef980394
--- /dev/null
+++ b/exercises/practice/strain/.meta/exercise-data.yaml
@@ -0,0 +1,93 @@
+subs: keep discard
+tests: |-
+  my ( $input, $expected, $function );
+
+  $input    = [];
+  $expected = [];
+  $function = sub { my $x = shift; $x % 2 == 0 };
+  is( keep( $input, $function ), $expected, "empty list" );
+
+  $input    = [ 2, 4, 6, 8, 10 ];
+  $expected = [];
+  $function = sub { my $x = shift; $x % 2 == 1 };
+  is( keep( $input, $function ),
+    $expected, "keep odd numbers. empty result " );
+
+  $input    = [ 2, 4, 6, 8, 10 ];
+  $expected = [];
+  $function = sub { my $x = shift; $x % 2 == 0 };
+  is( discard( $input, $function ),
+    $expected, "discard even numbers. empty result" );
+
+  $input    = [ 2, 4, 6, 8, 10 ];
+  $expected = [ 2, 4, 6, 8, 10 ];
+  $function = sub { my $x = shift; $x % 2 == 0 };
+  is( keep( $input, $function ),
+    $expected, "keep even numbers. result == input" );
+
+  $input    = [qw(dough cash plough though through enough)];
+  $expected = ['cash'];
+  $function = sub { my $x = shift; $x =~ m/ough$/ };
+  is( discard( $input, $function ),
+    $expected, "discard input endswith 'ough'" );
+
+  $input    = [qw(zebra arizona apple google mozilla)];
+  $expected = [qw(zebra arizona mozilla)];
+  $function = sub { my $x = shift; $x =~ /z/ };
+  is( keep( $input, $function ),
+    $expected, "keep input with 'z'" );
+
+  $input    = [ '1,2,3', 'one', 'almost!', 'love' ];
+  $expected = [];
+  $function = sub { my $x = shift; $x =~ /\p{IsAlpha}/ };
+  is( discard( keep( $input, $function ) // [], $function ),
+    $expected, "keep then discard" );
+
+  $input    = [ '1,2,3', 'one', 'almost!', 'love' ];
+  $expected = [ '1,2,3', 'one', 'almost!', 'love' ];
+  $function = sub { my $x = shift; $x =~ /\p{Alpha}/ };
+  my $combined = [
+    @{ keep( $input, $function ) // [] },
+    @{ discard( $input, $function ) // [] }
+  ];
+  is(
+    [ sort @$combined ],
+    [ sort @$expected ],
+    "combine keep and discard results. keep + discard"
+  );
+
+example: |-
+  sub keep    { [ _filter( @_, 1 ) ] }
+  sub discard { [ _filter( @_, 0 ) ] }
+
+  sub _filter {
+    my ( $list, $function, $is_keeping ) = @_;
+
+    die "ArgumentError: 2nd parameter must be a function reference"
+      unless ref $function eq 'CODE';
+
+    my @result;
+
+    foreach my $element (@$list) {
+      if ($is_keeping) {
+        push @result, $element if $function->($element);
+        next;
+      }
+
+      # discard
+      push @result, $element unless $function->($element);
+    }
+
+    return @result;
+  }
+
+stub: |-
+  sub keep {
+    my ($input, $function) = @_;
+    return undef;
+  }
+
+  sub discard {
+    my ($input, $function) = @_;
+    return undef;
+  }
diff --git a/exercises/practice/strain/.meta/solutions/Strain.pm b/exercises/practice/strain/.meta/solutions/Strain.pm
index 8dbca995..3072bce5 100644
--- a/exercises/practice/strain/.meta/solutions/Strain.pm
+++ b/exercises/practice/strain/.meta/solutions/Strain.pm
@@ -1,7 +1,8 @@
 package Strain;
-
 use strict;
 use warnings;
+use Exporter qw<import>;
+our @EXPORT_OK = qw<keep discard>;
 
 sub keep    { [ _filter( @_, 1 ) ] }
 sub discard { [ _filter( @_, 0 ) ] }
diff --git a/exercises/practice/strain/Strain.pm b/exercises/practice/strain/Strain.pm
new file mode 100644
index 00000000..df954a4c
--- /dev/null
+++ b/exercises/practice/strain/Strain.pm
@@ -0,0 +1,17 @@
+package Strain;
+use strict;
+use warnings;
+use Exporter qw<import>;
+our @EXPORT_OK = qw<keep discard>;
+
+sub keep {
+  my ( $input, $function ) = @_;
+  return undef;
+}
+
+sub discard {
+  my ( $input, $function ) = @_;
+  return undef;
+}
+
+1;
diff --git a/exercises/practice/strain/strain.t b/exercises/practice/strain/strain.t
old mode 100644
new mode 100755
index af349f45..40aeed11
--- a/exercises/practice/strain/strain.t
+++ b/exercises/practice/strain/strain.t
@@ -1,82 +1,66 @@
 #!/usr/bin/env perl
-use strict;
-use warnings;
+use Test2::V0;
 
-use Test2::Bundle::More;
-use FindBin qw($Bin);
+use FindBin qw<$Bin>;
 use lib $Bin, "$Bin/local/lib/perl5";
 
-my $module = 'Strain';
+use Strain qw<keep discard>;
 
-plan 12;
+imported_ok qw<keep discard> or bail_out;
 
-ok -e "$Bin/$module.pm", "Missing $module.pm"
-  or BAIL_OUT "You need to create file $module.pm";
-
-eval "use $module";
-ok !$@, "Cannot load $module"
-  or BAIL_OUT
-  "Cannot load $module. Does it compile? Does it end with 1;?";
-
-can_ok $module, "keep"
-  or BAIL_OUT "Missing package $module or missing sub keep()";
-can_ok $module, "discard"
-  or BAIL_OUT "Missing package $module or missing sub discard()";
-
-my $keep    = \&{"${module}::keep"};
-my $discard = \&{"${module}::discard"};
 my ( $input, $expected, $function );
 
 $input    = [];
 $expected = [];
 $function = sub { my $x = shift; $x % 2 == 0 };
-is_deeply( $keep->( $input, $function ), $expected, "empty list" );
+is( keep( $input, $function ), $expected, "empty list" );
 
 $input    = [ 2, 4, 6, 8, 10 ];
 $expected = [];
 $function = sub { my $x = shift; $x % 2 == 1 };
-is_deeply( $keep->( $input, $function ),
+is( keep( $input, $function ),
   $expected, "keep odd numbers. empty result " );
 
 $input    = [ 2, 4, 6, 8, 10 ];
 $expected = [];
 $function = sub { my $x = shift; $x % 2 == 0 };
-is_deeply( $discard->( $input, $function ),
+is( discard( $input, $function ),
   $expected, "discard even numbers. empty result" );
 
 $input    = [ 2, 4, 6, 8, 10 ];
 $expected = [ 2, 4, 6, 8, 10 ];
 $function = sub { my $x = shift; $x % 2 == 0 };
-is_deeply( $keep->( $input, $function ),
+is( keep( $input, $function ),
   $expected, "keep even numbers. result == input" );
 
 $input    = [qw(dough cash plough though through enough)];
 $expected = ['cash'];
 $function = sub { my $x = shift; $x =~ m/ough$/ };
-is_deeply( $discard->( $input, $function ),
+is( discard( $input, $function ),
   $expected, "discard input endswith 'ough'" );
 
 $input    = [qw(zebra arizona apple google mozilla)];
 $expected = [qw(zebra arizona mozilla)];
 $function = sub { my $x = shift; $x =~ /z/ };
-is_deeply( $keep->( $input, $function ),
-  $expected, "keep input with 'z'" );
+is( keep( $input, $function ), $expected, "keep input with 'z'" );
 
 $input    = [ '1,2,3', 'one', 'almost!', 'love' ];
 $expected = [];
 $function = sub { my $x = shift; $x =~ /\p{IsAlpha}/ };
-is_deeply( $discard->( $keep->( $input, $function ), $function ),
+is( discard( keep( $input, $function ) // [], $function ),
   $expected, "keep then discard" );
 
 $input    = [ '1,2,3', 'one', 'almost!', 'love' ];
 $expected = [ '1,2,3', 'one', 'almost!', 'love' ];
 $function = sub { my $x = shift; $x =~ /\p{Alpha}/ };
 my $combined = [
-  @{ $keep->( $input, $function ) },
-  @{ $discard->( $input, $function ) }
+  @{ keep( $input, $function )    // [] },
+  @{ discard( $input, $function ) // [] }
 ];
-is_deeply(
+is(
   [ sort @$combined ],
   [ sort @$expected ],
   "combine keep and discard results. keep + discard"
 );
+
+done_testing;
diff --git a/exercises/practice/trinary/Trinary.pm b/exercises/practice/trinary/Trinary.pm
new file mode 100644
index 00000000..f0674927
--- /dev/null
+++ b/exercises/practice/trinary/Trinary.pm
@@ -0,0 +1,17 @@
+package Trinary;
+
+use strict;
+use warnings;
+
+sub new {
+  my ( $class, $trinary ) = @_;
+  
+  return undef;
+}
+
+sub to_decimal {
+  my $self = shift;
+
+  return undef;
+}
+__PACKAGE__;