1 files changed, 86 insertions, 1 deletions
diff --git a/spec/ruby/library/coverage/start_spec.rb b/spec/ruby/library/coverage/start_spec.rb
index ddfad8b47c..7fccf2d5cf 100644
--- a/spec/ruby/library/coverage/start_spec.rb
+++ b/spec/ruby/library/coverage/start_spec.rb
@@ -2,5 +2,90 @@ require_relative '../../spec_helper'
 require 'coverage'
 
 describe 'Coverage.start' do
-  it 'needs to be reviewed for spec completeness'
+  before :each do
+    Coverage.should_not.running?
+  end
+
+  after :each do
+    Coverage.result(stop: true, clear: true) if Coverage.running?
+  end
+
+  it "enables the coverage measurement" do
+    Coverage.start
+    Coverage.should.running?
+  end
+
+  it "returns nil" do
+    Coverage.start.should == nil
+  end
+
+  ruby_version_is '3.1' do
+    it 'raises error when repeated Coverage.start call happens' do
+      Coverage.start
+
+      -> {
+        Coverage.start
+      }.should raise_error(RuntimeError, 'coverage measurement is already setup')
+    end
+  end
+
+  ruby_version_is '3.2' do
+    it "accepts :all optional argument" do
+      Coverage.start(:all)
+      Coverage.should.running?
+    end
+
+    it "accepts lines: optional keyword argument" do
+      Coverage.start(lines: true)
+      Coverage.should.running?
+    end
+
+    it "accepts branches: optional keyword argument" do
+      Coverage.start(branches: true)
+      Coverage.should.running?
+    end
+
+    it "accepts methods: optional keyword argument" do
+      Coverage.start(methods: true)
+      Coverage.should.running?
+    end
+
+    it "accepts eval: optional keyword argument" do
+      Coverage.start(eval: true)
+      Coverage.should.running?
+    end
+
+    it "accepts oneshot_lines: optional keyword argument" do
+      Coverage.start(oneshot_lines: true)
+      Coverage.should.running?
+    end
+
+    it "ignores unknown keyword arguments" do
+      Coverage.start(foo: true)
+      Coverage.should.running?
+    end
+
+    it "expects a Hash if not passed :all" do
+      -> {
+        Coverage.start(42)
+      }.should raise_error(TypeError, "no implicit conversion of Integer into Hash")
+    end
+
+    it "does not accept both lines: and oneshot_lines: keyword arguments" do
+      -> {
+        Coverage.start(lines: true, oneshot_lines: true)
+      }.should raise_error(RuntimeError, "cannot enable lines and oneshot_lines simultaneously")
+    end
+
+    it "enables the coverage measurement if passed options with `false` value" do
+      Coverage.start(lines: false, branches: false, methods: false, eval: false, oneshot_lines: false)
+      Coverage.should.running?
+    end
+
+    it "measures coverage within eval" do
+      Coverage.start(lines: true, eval: true)
+      eval("Object.new\n"*3, binding, "test.rb", 1)
+      Coverage.result["test.rb"].should == {lines: [1, 1, 1]}
+    end
+  end
 end