Case statements should be counted as branches (#493)

* Case statements should be counted as branches

* Run scalafmt

Author: jrglee

plugin/src/main/scala/scoverage/ScoveragePlugin.scala

@@ -213,13 +213,17 @@ class ScoverageInstrumentationComponent(
         }) ++ cases.takeRight(1)
     }
 
-    def transformCases(cases: List[CaseDef]): List[CaseDef] = {
+    def transformCases(
+        cases: List[CaseDef],
+        branch: Boolean = false
+    ): List[CaseDef] = {
       cases.map(c => {
         treeCopy.CaseDef(
           c,
           c.pat,
           process(c.guard),
-          process(c.body)
+          if (branch) instrument(process(c.body), c.body, branch = true)
+          else process(c.body)
         )
       })
     }
@@ -392,7 +396,7 @@ class ScoverageInstrumentationComponent(
                       // note: do not transform last case as that is the default handling
                       d.rhs,
                       selector,
-                      transformCases(cases.init) :+ cases.last
+                      transformCases(cases.init, branch = true) :+ cases.last
                     )
                   )
                 case _ =>
@@ -697,7 +701,11 @@ class ScoverageInstrumentationComponent(
               treeCopy.Match(tree, selector, transformCases(cases))
             else
               // .. but we will if it was a user match
-              treeCopy.Match(tree, process(selector), transformCases(cases))
+              treeCopy.Match(
+                tree,
+                process(selector),
+                transformCases(cases, branch = true)
+              )
           }
 
         // a synthetic object is a generated object, such as case class companion
@@ -791,7 +799,7 @@ class ScoverageInstrumentationComponent(
           treeCopy.Try(
             tree,
             instrument(process(t), t, branch = true),
-            transformCases(cases),
+            transformCases(cases, branch = true),
             if (f.isEmpty) f else instrument(process(f), f, branch = true)
           )
 

plugin/src/test/scala/scoverage/PluginCoverageTest.scala

@@ -79,9 +79,9 @@ class PluginCoverageTest extends FunSuite with MacroSupport {
     assert(!compiler.reporter.hasWarnings)
 
     /** should have the following statements instrumented:
-      * the selector, clause 1
+      * the selector, clause/skip 1
       */
-    compiler.assertNMeasuredStatements(2)
+    compiler.assertNMeasuredStatements(3)
   }
   test("scoverage should instrument match guards") {
     val compiler = ScoverageCompiler.default
@@ -98,7 +98,7 @@ class PluginCoverageTest extends FunSuite with MacroSupport {
     /** should have the following statements instrumented:
       * the selector, guard 1, clause 1, guard 2, clause 2, clause 3
       */
-    compiler.assertNMeasuredStatements(6)
+    compiler.assertNMeasuredStatements(9)
   }
 
   test("scoverage should instrument non basic selector") {
@@ -114,7 +114,8 @@ class PluginCoverageTest extends FunSuite with MacroSupport {
     // the someValue method entry
     // the selector call
     // case block "yes" literal
-    compiler.assertNMeasuredStatements(3)
+    // skip case block
+    compiler.assertNMeasuredStatements(4)
   }
 
   test("scoverage should instrument conditional selectors in a match") {
@@ -134,7 +135,8 @@ class PluginCoverageTest extends FunSuite with MacroSupport {
     // elsep block,
     // elsep literal "2",
     // case block "yes" literal
-    compiler.assertNMeasuredStatements(6)
+    // skip case block "yes" literal
+    compiler.assertNMeasuredStatements(7)
   }
 
   // https://github.com/scoverage/sbt-scoverage/issues/16
@@ -261,8 +263,9 @@ class PluginCoverageTest extends FunSuite with MacroSupport {
     assert(!compiler.reporter.hasErrors)
     assert(!compiler.reporter.hasWarnings)
     // should have one statement for each case body
+    // and one statement for each case skipped
     // selector is a constant so would be ignored.
-    compiler.assertNMeasuredStatements(3)
+    compiler.assertNMeasuredStatements(6)
   }
 
   test("plugin should support yields") {