Class: CouchPotato::RSpec::MapReduceToMatcher

Inherits:
Object
  • Object
show all
Includes:
RunJS
Defined in:
lib/couch_potato/rspec/matchers/map_reduce_to_matcher.rb

Instance Method Summary (collapse)

Constructor Details

- (MapReduceToMatcher) initialize(expected_ruby, input_ruby, options)

Returns a new instance of MapReduceToMatcher



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# File 'lib/couch_potato/rspec/matchers/map_reduce_to_matcher.rb', line 23

def initialize(expected_ruby, input_ruby, options)
  @expected_ruby = expected_ruby
  @input_ruby = input_ruby
  @options = options
end

Instance Method Details

- (Object) failure_message_for_should



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# File 'lib/couch_potato/rspec/matchers/map_reduce_to_matcher.rb', line 156

def failure_message_for_should
  "Expected to map/reduce to #{@expected_ruby.inspect} but got #{@actual_ruby.inspect}."
end

- (Object) failure_message_for_should_not



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# File 'lib/couch_potato/rspec/matchers/map_reduce_to_matcher.rb', line 160

def failure_message_for_should_not
  "Expected not to map/reduce to #{@actual_ruby.inspect} but did."
end

- (Boolean) matches?(view_spec)

Returns:

  • (Boolean)


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# File 'lib/couch_potato/rspec/matchers/map_reduce_to_matcher.rb', line 29

def matches?(view_spec)
  js = <<-JS
    var sum = function(values) {
      return values.reduce(function(memo, value) { return memo + value; });
    };
    // Equivalents of couchdb built-in reduce functions whose names can be
    // given as the reduce function in the view_spec:
    var _sum = function(keys, values, rereduce) {
      return sum(values);
    }
    var _count = function(keys, values, rereduce) {
      if (rereduce) {
        return sum(values);
      } else {
        return values.length;
      }
    }
    var _stats = function(keys, values, rereduce) {
      var result = {sum: 0, count: 0, min: Number.MAX_VALUE, max: Number.MIN_VALUE, sumsqr: 0};
      if (rereduce) {
        for (var i in values) {
          var value = values[i];
          result.sum += value.sum;
          result.count += value.count;
          result.min = Math.min(result.min, value.min);
          result.max = Math.max(result.max, value.max);
          result.sumsqr += value.sumsqr;
        }
      } else {
        for (var i in values) {
          var value = values[i];
          result.sum += value;
          result.count += 1;
          result.min = Math.min(result.min, value);
          result.max = Math.max(result.max, value);
          result.sumsqr += Math.pow(value, 2);
        }
      }
      return result;
    }

    var docs = #{@input_ruby.to_json};
    var options = #{@options.to_json};
    var map = #{view_spec.map_function};
    var reduce = #{view_spec.reduce_function};
    var lib = #{view_spec.respond_to?(:lib) && view_spec.lib.to_json};

    // Map the input docs
    var require = function(modulePath) {
      var exports = {};
      var pathArray = modulePath.split("/").slice(2);
      var result = lib;
      for (var i in pathArray) {
        result = result[pathArray[i]]
      }
      eval(result);
      return exports;
    }

    var mapResults = [];
    var emit = function(key, value) {
      mapResults.push({key: key, value: value});
    };
    for (var i in docs) {
      map(docs[i]);
    }

    // Group the map results, honoring the group and group_level options
    var grouped = [];
    if (options.group || options.group_level) {
      var groupLevel = options.group_level;
      if (groupLevel == "exact" || options.group == true)
        groupLevel = 9999;
      var keysEqual = function(a, b) { return !(a < b || b < a); }

      for (var mr in mapResults) {
        var mapResult = mapResults[mr];
        var groupedKey = mapResult.key.slice(0, groupLevel);
        var groupFound = false;
        for (var g in grouped) {
          var group = grouped[g];
          if (keysEqual(groupedKey, group.groupedKey)) {
            group.keys.push(mapResult.key);
            group.values.push(mapResult.value);
            groupFound = true;
            break;
          }
        }

        if (!groupFound)
          grouped.push({keys: [mapResult.key], groupedKey: groupedKey, values: [mapResult.value]});
      }
    } else {
      var group = {keys: null, groupedKey: null, values: []};
      for (var mr in mapResults)
        group.values.push(mapResults[mr].value);
      grouped.push(group);
    }

    // Reduce the grouped map results
    var results = [];
    for (var g in grouped) {
      var group = grouped[g], reduced = null;
      if (group.values.length >= 2) {
        // Split the values into two parts, reduce each part, then rereduce those results
        var mid = parseInt(group.values.length / 2);
        var keys1 = (group.keys || []).slice(0, mid),
            values1 = group.values.slice(0, mid);
        var reduced1 = reduce(keys1, values1, false);
        var keys2 = (group.keys || []).slice(mid, group.values.length),
            values2 = group.values.slice(mid, group.values.length);
        var reduced2 = reduce(keys2, values2, false);
        reduced = reduce(null, [reduced1, reduced2], true);
      } else {
        // Not enough values to split, so just reduce, and then rereduce the single result
        reduced = reduce(group.keys, group.values, false);
        reduced = reduce(null, [reduced], true);
      }
      results.push({key: group.groupedKey, value: reduced});
    }

    JSON.stringify(results);
  JS
  @actual_ruby = JSON.parse(run_js(js))
  @expected_ruby == @actual_ruby
end