From a72f5110dc157202347daacaa81e0cda18d736eb Mon Sep 17 00:00:00 2001
From: Markus Schirp <mbj@schirp-dso.com>
Date: Thu, 29 Oct 2020 14:45:29 +0000
Subject: [PATCH] Change minitest integration to allow multiple cover
 expressions

---
 lib/mutant/integration/minitest.rb          | 17 ++++++++++-------
 lib/mutant/minitest/coverage.rb             | 18 ++++++++----------
 test_app/test/unit/test_app/literal_test.rb |  1 +
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/lib/mutant/integration/minitest.rb b/lib/mutant/integration/minitest.rb
index e957d41c0..49abfe542 100644
--- a/lib/mutant/integration/minitest.rb
+++ b/lib/mutant/integration/minitest.rb
@@ -51,13 +51,16 @@ def call(reporter)
           reporter.passed?
         end
 
-        # Cover expression syntaxes
+        # Parse expressions
         #
-        # @return [String, nil]
-        def expression_syntax
-          klass.resolve_cover_expression
+        # @param [ExpressionParser] parser
+        #
+        # @return [Array<Expression>]
+        def expressions(parser)
+          klass.resolve_cover_expression.map do |syntax|
+            parser.apply(syntax).from_right
+          end
         end
-
       end # TestCase
 
       private_constant(*constants(false))
@@ -125,7 +128,7 @@ def all_tests_index
       def construct_test(test_case)
         Test.new(
           id:          test_case.identification,
-          expressions: [config.expression_parser.apply(test_case.expression_syntax).from_right]
+          expressions: test_case.expressions(parser)
         )
       end
 
@@ -137,7 +140,7 @@ def all_test_cases
       end
 
       def allow_runnable?(klass)
-        !klass.equal?(::Minitest::Runnable) && klass.resolve_cover_expression
+        !klass.equal?(::Minitest::Runnable) && klass.resolve_cover_expressions
       end
 
       def test_case(runnable)
diff --git a/lib/mutant/minitest/coverage.rb b/lib/mutant/minitest/coverage.rb
index 7acec17b4..c8ea51ef7 100644
--- a/lib/mutant/minitest/coverage.rb
+++ b/lib/mutant/minitest/coverage.rb
@@ -20,30 +20,28 @@ module Coverage
       #
       # @api public
       def cover(expression)
-        if defined?(@cover_expression)
-          fail "#{self} already declares to cover: #{@cover_expression.inspect}"
-        end
+        @cover_expressions = Set.new unless defined?(@cover_expressions)
 
-        @cover_expression = expression
+        @cover_expressions << expression
       end
 
       # Effective coverage expression
       #
-      # @return [String, nil]
+      # @return [Set<String>]
       #
       # @api private
-      def resolve_cover_expression
-        return @cover_expression if defined?(@cover_expression)
+      def resolve_cover_expressions
+        return @cover_expressions if defined?(@cover_expressions)
 
-        try_superclass_cover_expression
+        try_superclass_cover_expressions
       end
 
     private
 
-      def try_superclass_cover_expression
+      def try_superclass_cover_expressions
         return if superclass.equal?(::Minitest::Runnable)
 
-        superclass.resolve_cover_expression
+        superclass.resolve_cover_expressions
       end
 
     end # Coverage
diff --git a/test_app/test/unit/test_app/literal_test.rb b/test_app/test/unit/test_app/literal_test.rb
index 52837f56a..2f8e27f39 100644
--- a/test_app/test/unit/test_app/literal_test.rb
+++ b/test_app/test/unit/test_app/literal_test.rb
@@ -3,6 +3,7 @@
 
 class LiteralTest < Minitest::Test
   cover 'TestApp::Literal*'
+  cover 'TestApp::Literal#string'
 
   def test_command
     object = ::TestApp::Literal.new