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to Clock in the Raku Track

Published at Apr 02 2021 · 0 comments
Instructions
Test suite
Solution

Implement a clock that handles times without dates.

You should be able to add and subtract minutes to it.

Two clocks that represent the same time should be equal to each other.

Resources

Remember to check out the Raku documentation and resources pages for information, tips, and examples if you get stuck.

Running the tests

There is a test suite and module included with the exercise. The test suite (a file with the extension .rakutest) will attempt to run routines from the module (a file with the extension .rakumod). Add/modify routines in the module so that the tests will pass! You can view the test data by executing the command raku --doc *.rakutest (* being the name of the test suite), and run the test suite for the exercise by executing the command prove6 . in the exercise directory.

Source

Pairing session with Erin Drummond https://twitter.com/ebdrummond

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

clock.rakutest

#!/usr/bin/env raku
use Test;
use JSON::Fast;
use lib $?FILE.IO.dirname;
use Clock;
plan 55;

subtest 'Class methods', {
  for <time add-minutes subtract-minutes> -> $method {
    can-ok Clock, $method;
  }
} or bail-out 'Cannot run expected method(s).';

my @test-cases = from-json($=pod.pop.contents).List;
for @test-cases -> %case {
  given %case<property> {

    when 'create' {
      is Clock.new( |%(.<input><hour minute>:p) ).time,
        |.<expected description> given %case;
    }

    when <add subtract>.any {
      given %case {
        my $clock = Clock.new: |%(.<input><hour minute>:p);
        $clock.add-minutes: .<input><value>
          if .<property> eq 'add';
        $clock.subtract-minutes: .<input><value>
          if .<property> eq 'subtract';
        is $clock.time, |.<expected description>;
      }
    }

    when 'equal' {
      is-deeply ([eq] gather {
        take Clock.new( |%(.<hour minute>:p) ).time
          for %case<input><clock1 clock2>;
      }), |%case<expected description>;
    }

  }
}

is Clock.new(:0hour,:0minute).add-minutes(65).?time,
  '01:05', 'add-minutes method can be chained';

is Clock.new(:0hour,:0minute).subtract-minutes(65).?time,
  '22:55', 'subtract-minutes method can be chained';

CATCH {
  when X::StubCode {
    flunk 'Caught stub';
    note "{.message} (does the sub/method contain '!!!'?)\n"
      ~ .backtrace.concise;
  }
}

=head2 Test Cases
=begin code
[
  {
    "description": "Create a new clock with an initial time: on the hour",
    "expected": "08:00",
    "input": {
      "hour": 8,
      "minute": 0
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: past the hour",
    "expected": "11:09",
    "input": {
      "hour": 11,
      "minute": 9
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: midnight is zero hours",
    "expected": "00:00",
    "input": {
      "hour": 24,
      "minute": 0
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: hour rolls over",
    "expected": "01:00",
    "input": {
      "hour": 25,
      "minute": 0
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: hour rolls over continuously",
    "expected": "04:00",
    "input": {
      "hour": 100,
      "minute": 0
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: sixty minutes is next hour",
    "expected": "02:00",
    "input": {
      "hour": 1,
      "minute": 60
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: minutes roll over",
    "expected": "02:40",
    "input": {
      "hour": 0,
      "minute": 160
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: minutes roll over continuously",
    "expected": "04:43",
    "input": {
      "hour": 0,
      "minute": 1723
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: hour and minutes roll over",
    "expected": "03:40",
    "input": {
      "hour": 25,
      "minute": 160
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: hour and minutes roll over continuously",
    "expected": "11:01",
    "input": {
      "hour": 201,
      "minute": 3001
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: hour and minutes roll over to exactly midnight",
    "expected": "00:00",
    "input": {
      "hour": 72,
      "minute": 8640
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative hour",
    "expected": "23:15",
    "input": {
      "hour": -1,
      "minute": 15
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative hour rolls over",
    "expected": "23:00",
    "input": {
      "hour": -25,
      "minute": 0
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative hour rolls over continuously",
    "expected": "05:00",
    "input": {
      "hour": -91,
      "minute": 0
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative minutes",
    "expected": "00:20",
    "input": {
      "hour": 1,
      "minute": -40
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative minutes roll over",
    "expected": "22:20",
    "input": {
      "hour": 1,
      "minute": -160
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative minutes roll over continuously",
    "expected": "16:40",
    "input": {
      "hour": 1,
      "minute": -4820
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative sixty minutes is previous hour",
    "expected": "01:00",
    "input": {
      "hour": 2,
      "minute": -60
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative hour and minutes both roll over",
    "expected": "20:20",
    "input": {
      "hour": -25,
      "minute": -160
    },
    "property": "create"
  },
  {
    "description": "Create a new clock with an initial time: negative hour and minutes both roll over continuously",
    "expected": "22:10",
    "input": {
      "hour": -121,
      "minute": -5810
    },
    "property": "create"
  },
  {
    "description": "Add minutes: add minutes",
    "expected": "10:03",
    "input": {
      "hour": 10,
      "minute": 0,
      "value": 3
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add no minutes",
    "expected": "06:41",
    "input": {
      "hour": 6,
      "minute": 41,
      "value": 0
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add to next hour",
    "expected": "01:25",
    "input": {
      "hour": 0,
      "minute": 45,
      "value": 40
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add more than one hour",
    "expected": "11:01",
    "input": {
      "hour": 10,
      "minute": 0,
      "value": 61
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add more than two hours with carry",
    "expected": "03:25",
    "input": {
      "hour": 0,
      "minute": 45,
      "value": 160
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add across midnight",
    "expected": "00:01",
    "input": {
      "hour": 23,
      "minute": 59,
      "value": 2
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add more than one day (1500 min = 25 hrs)",
    "expected": "06:32",
    "input": {
      "hour": 5,
      "minute": 32,
      "value": 1500
    },
    "property": "add"
  },
  {
    "description": "Add minutes: add more than two days",
    "expected": "11:21",
    "input": {
      "hour": 1,
      "minute": 1,
      "value": 3500
    },
    "property": "add"
  },
  {
    "description": "Subtract minutes: subtract minutes",
    "expected": "10:00",
    "input": {
      "hour": 10,
      "minute": 3,
      "value": 3
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract to previous hour",
    "expected": "09:33",
    "input": {
      "hour": 10,
      "minute": 3,
      "value": 30
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract more than an hour",
    "expected": "08:53",
    "input": {
      "hour": 10,
      "minute": 3,
      "value": 70
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract across midnight",
    "expected": "23:59",
    "input": {
      "hour": 0,
      "minute": 3,
      "value": 4
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract more than two hours",
    "expected": "21:20",
    "input": {
      "hour": 0,
      "minute": 0,
      "value": 160
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract more than two hours with borrow",
    "expected": "03:35",
    "input": {
      "hour": 6,
      "minute": 15,
      "value": 160
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract more than one day (1500 min = 25 hrs)",
    "expected": "04:32",
    "input": {
      "hour": 5,
      "minute": 32,
      "value": 1500
    },
    "property": "subtract"
  },
  {
    "description": "Subtract minutes: subtract more than two days",
    "expected": "00:20",
    "input": {
      "hour": 2,
      "minute": 20,
      "value": 3000
    },
    "property": "subtract"
  },
  {
    "description": "Compare two clocks for equality: clocks with same time",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 15,
        "minute": 37
      },
      "clock2": {
        "hour": 15,
        "minute": 37
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks a minute apart",
    "expected": false,
    "input": {
      "clock1": {
        "hour": 15,
        "minute": 36
      },
      "clock2": {
        "hour": 15,
        "minute": 37
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks an hour apart",
    "expected": false,
    "input": {
      "clock1": {
        "hour": 14,
        "minute": 37
      },
      "clock2": {
        "hour": 15,
        "minute": 37
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with hour overflow",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 10,
        "minute": 37
      },
      "clock2": {
        "hour": 34,
        "minute": 37
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with hour overflow by several days",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 3,
        "minute": 11
      },
      "clock2": {
        "hour": 99,
        "minute": 11
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative hour",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 22,
        "minute": 40
      },
      "clock2": {
        "hour": -2,
        "minute": 40
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative hour that wraps",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 17,
        "minute": 3
      },
      "clock2": {
        "hour": -31,
        "minute": 3
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative hour that wraps multiple times",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 13,
        "minute": 49
      },
      "clock2": {
        "hour": -83,
        "minute": 49
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with minute overflow",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 0,
        "minute": 1
      },
      "clock2": {
        "hour": 0,
        "minute": 1441
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with minute overflow by several days",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 2,
        "minute": 2
      },
      "clock2": {
        "hour": 2,
        "minute": 4322
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative minute",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 2,
        "minute": 40
      },
      "clock2": {
        "hour": 3,
        "minute": -20
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative minute that wraps",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 4,
        "minute": 10
      },
      "clock2": {
        "hour": 5,
        "minute": -1490
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative minute that wraps multiple times",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 6,
        "minute": 15
      },
      "clock2": {
        "hour": 6,
        "minute": -4305
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative hours and minutes",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 7,
        "minute": 32
      },
      "clock2": {
        "hour": -12,
        "minute": -268
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: clocks with negative hours and minutes that wrap",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 18,
        "minute": 7
      },
      "clock2": {
        "hour": -54,
        "minute": -11513
      }
    },
    "property": "equal"
  },
  {
    "description": "Compare two clocks for equality: full clock and zeroed clock",
    "expected": true,
    "input": {
      "clock1": {
        "hour": 24,
        "minute": 0
      },
      "clock2": {
        "hour": 0,
        "minute": 0
      }
    },
    "property": "equal"
  }
]
=end code
unit class Clock;
has $.hour = 0;
has $.minute = 0;

submethod TWEAK() { self!normalize }

method !normalize {
    $!hour = ($!hour + $!minute div 60) % 24 ;
    $!minute %= 60 ;
    self
}

method time { '%02i:%02i'.sprintf: $!hour , $!minute }

method add-minutes ($amount) {
    $!minute += $amount ;
    self!normalize
}

method subtract-minutes ($amount) {
    $!minute -= $amount ;
    self!normalize
}

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