Rename CoverageData to CoverageStatistics

*Data was an unfortunate name, as in SourceFile that's what the
attribute holding the well... actual coverage data emitted from
the coverage library. All in all it's statistics for display
and that should be helpful and neat, and not clash with other
names.

lib/simplecov.rb

@@ -417,7 +417,7 @@ def result_with_not_loaded_files
 require "forwardable"
 require "simplecov/configuration"
 SimpleCov.extend SimpleCov::Configuration
-require "simplecov/coverage_data"
+require "simplecov/coverage_statistics"
 require "simplecov/exit_codes"
 require "simplecov/profiles"
 require "simplecov/source_file/line"

lib/simplecov/coverage_data.rb → lib/simplecov/coverage_statistics.rb

@@ -10,18 +10,18 @@ module SimpleCov
   # * missed - how many of the coverables are missed
   # * percent - percentage as covered/missed
   # * strength - average hits per/coverable (will not exist for one shot lines format)
-  class CoverageData
+  class CoverageStatistics
     attr_reader :total, :covered, :missed, :strength, :percent
 
-    def self.from(coverage_data)
+    def self.from(coverage_statistics)
       sum_covered, sum_missed, sum_total_strength =
-        coverage_data.reduce([0, 0, 0.0]) do |(covered, missed, total_strength), file_coverage_data|
+        coverage_statistics.reduce([0, 0, 0.0]) do |(covered, missed, total_strength), file_coverage_statistics|
           [
-            covered + file_coverage_data.covered,
-            missed + file_coverage_data.missed,
+            covered + file_coverage_statistics.covered,
+            missed + file_coverage_statistics.missed,
             # gotta remultiply with loc because files have different strenght and loc
             # giving them a different "weight" in total
-            total_strength + (file_coverage_data.strength * file_coverage_data.total)
+            total_strength + (file_coverage_statistics.strength * file_coverage_statistics.total)
           ]
         end
 

lib/simplecov/file_list.rb

@@ -101,14 +101,14 @@ def branch_covered_percent
   private
 
     def compute_coverage
-      total_coverage_data = @files.each_with_object(line: [], branch: []) do |file, together|
+      total_coverage_statistics = @files.each_with_object(line: [], branch: []) do |file, together|
         together[:line] << file.coverage[:line]
         together[:branch] << file.coverage[:branch] if SimpleCov.branch_coverage?
       end
 
-      coverage_data = {line: CoverageData.from(total_coverage_data[:line])}
-      coverage_data[:branch] = CoverageData.from(total_coverage_data[:branch]) if SimpleCov.branch_coverage?
-      coverage_data
+      coverage_statistics = {line: CoverageStatistics.from(total_coverage_statistics[:line])}
+      coverage_statistics[:branch] = CoverageStatistics.from(total_coverage_statistics[:branch]) if SimpleCov.branch_coverage?
+      coverage_statistics
     end
   end
 end

lib/simplecov/source_file.rb

@@ -280,7 +280,7 @@ def build_branch(branch_data, hit_count, condition_start_line)
 
     def line_coverage
       {
-        line: CoverageData.new(
+        line: CoverageStatistics.new(
           total_strength: lines_strength,
           covered:  covered_lines.size,
           missed:   missed_lines.size
@@ -290,7 +290,7 @@ def line_coverage
 
     def branch_coverage
       {
-        branch: CoverageData.new(
+        branch: CoverageStatistics.new(
           covered: covered_branches.size,
           missed:  missed_branches.size
         )

spec/coverage_statistics_spec.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require "helper"
+
+RSpec.describe SimpleCov::CoverageStatistics do
+  describe ".new" do
+    it "retains statistics and computes new ones" do
+      statistics = described_class.new(covered: 4, missed: 6, total_strength: 14)
+
+      expect(statistics.covered).to eq 4
+      expect(statistics.missed).to eq 6
+
+      expect(statistics.total).to eq 10
+      expect(statistics.percent).to eq 40.0
+      expect(statistics.strength).to eq 1.4
+    end
+
+    it "can omit the total strength defaulting to 0.0" do
+      statistics = described_class.new(covered: 4, missed: 6, total_strength: 0.0)
+
+      expect(statistics.strength).to eq 0.0
+    end
+
+    it "can deal with it if everything is 0" do
+      statistics = described_class.new(covered: 0, missed: 0, total_strength: 0.0)
+
+      expect_all_empty(statistics)
+    end
+  end
+
+  describe ".from" do
+    it "returns an all 0s coverage statistics if there is no statistics" do
+      statistics = described_class.from([])
+
+      expect_all_empty(statistics)
+    end
+
+    it "returns all empty statistics when initialized with a couple of empty results" do
+      statistics = described_class.from([empty_statistics, empty_statistics])
+
+      expect_all_empty(statistics)
+    end
+
+    it "produces sensible total results" do
+      statistics = described_class.from(
+        [
+          described_class.new(covered: 3, missed: 4, total_strength: 54),
+          described_class.new(covered: 0, missed: 13, total_strength: 0),
+          described_class.new(covered: 37, missed: 0, total_strength: 682)
+        ]
+      )
+
+      expect(statistics.covered).to eq 40
+      expect(statistics.missed).to eq 17
+      expect(statistics.total).to eq 57
+      expect(statistics.percent).to be_within(0.01).of(70.18)
+      expect(statistics.strength).to be_within(0.01).of(12.91)
+    end
+  end
+
+  def empty_statistics
+    described_class.new(covered: 0, missed: 0, total_strength: 0.0)
+  end
+
+  def expect_all_empty(statistics)
+    expect(statistics.covered).to eq 0
+    expect(statistics.missed).to eq 0
+
+    expect(statistics.total).to eq 0
+    # might be counter intuitive but think of it as "we covered everything we could"
+    expect(statistics.percent).to eq 100.0
+    expect(statistics.strength).to eq 0.0
+  end
+end