More thorough maximum coverage drop specs + fixes

* fixes accuracy bug in drop calculation
* fixes bug when no coverage data present from last run

lib/simplecov/exit_codes/maximum_coverage_drop_check.rb

@@ -51,22 +51,32 @@ def compute_coverage_drop_data
  {
  criterion: criterion,
  max_drop: percent,
- drop_percent: last_coverage(criterion) -
- SimpleCov.round_coverage(
- result.coverage_statistics.fetch(criterion).percent
- )
+ drop_percent: drop_percent(criterion)
  }
  end
  end
 
+ # if anyone says "max_coverage_drop 0.000000000000000001" I appologize. Please don't.
+ MAX_DROP_ACCURACY = 10
+ def drop_percent(criterion)
+ drop = last_coverage(criterion) -
+ SimpleCov.round_coverage(
+ result.coverage_statistics.fetch(criterion).percent
+ )
+
+ # floats, I tell ya.
+ # irb(main):001:0* 80.01 - 80.0
+ # => 0.010000000000005116
+ drop.floor(MAX_DROP_ACCURACY)
+ end
+
  def last_coverage(criterion)
  last_coverage_percent = last_run[:result][criterion]
 
- if !last_coverage_percent && criterion == :line
- last_run[:result][:covered_percent]
- else
- last_coverage_percent
- end
+ # fallback for old file format
+ last_coverage_percent = last_run[:result][:covered_percent] if !last_coverage_percent && criterion == :line
+
+ last_coverage_percent || 0
  end
  end
  end

spec/exit_codes/maximum_coverage_drop_check_spec.rb

@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require "helper"
+
+RSpec.describe SimpleCov::ExitCodes::MaximumCoverageDropCheck do
+ let(:result) do
+ instance_double(SimpleCov::Result, coverage_statistics: stats)
+ end
+ let(:stats) do
+ {
+ line: SimpleCov::CoverageStatistics.new(covered: 8, missed: 2),
+ branch: SimpleCov::CoverageStatistics.new(covered: 8, missed: 2)
+ }
+ end
+ let(:last_run) do
+ {
+ result: last_coverage
+ }
+ end
+ let(:last_coverage) { {line: 80.0, branch: 80.0} }
+ let(:maximum_coverage_drop) { {line: 0, branch: 0} }
+ subject { described_class.new(result, maximum_coverage_drop) }
+
+ before :each do
+ expect(SimpleCov::LastRun).to receive(:read).and_return(last_run)
+ end
+
+ context "we're at the same coverage" do
+ it { is_expected.not_to be_failing }
+ end
+
+ context "more coverage drop allowed" do
+ let(:maximum_coverage_drop) { {line: 10, branch: 10} }
+
+ it { is_expected.not_to be_failing }
+ end
+
+ context "last coverage lower then new coverage" do
+ let(:last_coverage) { {line: 70.0, branch: 70.0} }
+
+ it { is_expected.not_to be_failing }
+ end
+
+ context "last coverage higher than new coverage" do
+ let(:last_coverage) { {line: 80.01, branch: 80.01} }
+
+ it { is_expected.to be_failing }
+
+ context "but allowed drop is within range" do
+ let(:maximum_coverage_drop) { {line: 0.01, branch: 0.01} }
+
+ it { is_expected.not_to be_failing }
+ end
+ end
+
+ context "one coverage lower than maximum drop" do
+ let(:last_coverage) { {line: 80.01, branch: 70.0} }
+
+ it { is_expected.to be_failing }
+
+ context "but allowed drop is within range" do
+ let(:maximum_coverage_drop) { {line: 0.01} }
+
+ it { is_expected.not_to be_failing }
+ end
+ end
+
+ context "coverage expectation for a coverage that wasn't previously present" do
+ let(:last_coverage) { {line: 80.0} }
+ let(:maximum_coverage_drop) { {line: 0, branch: 0} }
+
+ it { is_expected.not_to be_failing }
+ end
+
+ context "no last run coverage information" do
+ let(:last_run) { nil }
+
+ it { is_expected.not_to be_failing }
+ end
+
+ context "old last_run.json format" do
+ let(:last_run) do
+ {
+ # this format only considers line coverage
+ result: {covered_percent: 80.0}
+ }
+ end
+
+ it { is_expected.not_to be_failing }
+ end
+end

spec/exit_codes/minimum_coverage_by_file_check_spec.rb

@@ -26,7 +26,6 @@
  let(:minimum_coverage_by_file) { {line: 90} }
 
  it "fails" do
- p minimum_coverage_by_file
  expect(subject).to be_failing
  end
  end