Add a simple set of evaluation tests for the various cross builds in `TestGraphs`, and a `crossResolved` test to exercise `mill.define.Cross.Resolver` functionality

3 files changed, 100 insertions, 5 deletions

diff --git a/core/test/src/mill/eval/CrossTests.scala b/core/test/src/mill/eval/CrossTests.scala
new file mode 100644
index 00000000..6ee48790
--- /dev/null
+++ b/core/test/src/mill/eval/CrossTests.scala
@@ -0,0 +1,77 @@
+package mill.eval
+
+import ammonite.ops._
+import mill.T
+import mill.define.Discover
+import mill.util.TestEvaluator
+import mill.util.TestGraphs.{crossResolved, doubleCross, nestedCrosses, singleCross}
+import utest._
+
+object CrossTests extends TestSuite{
+  val tests = Tests{
+    'singleCross - {
+      val check = new TestEvaluator(
+        singleCross,
+        Discover[singleCross.type],
+        pwd / 'target / 'workspace / "cross-tests" / "inputs",
+        pwd
+      )
+
+      val Right(("210", 1)) = check.apply(singleCross.cross("210").suffix)
+      val Right(("211", 1)) = check.apply(singleCross.cross("211").suffix)
+      val Right(("212", 1)) = check.apply(singleCross.cross("212").suffix)
+    }
+
+    'crossResolved - {
+      val check = new TestEvaluator(
+        crossResolved,
+        Discover[crossResolved.type],
+        pwd / 'target / 'workspace / "cross-tests" / "crossResolved",
+        pwd
+      )
+
+      val Right(("2.10", 1)) = check.apply(crossResolved.foo("2.10").suffix)
+      val Right(("2.11", 1)) = check.apply(crossResolved.foo("2.11").suffix)
+      val Right(("2.12", 1)) = check.apply(crossResolved.foo("2.12").suffix)
+
+      val Right(("_2.10", 1)) = check.apply(crossResolved.bar("2.10").longSuffix)
+      val Right(("_2.11", 1)) = check.apply(crossResolved.bar("2.11").longSuffix)
+      val Right(("_2.12", 1)) = check.apply(crossResolved.bar("2.12").longSuffix)
+    }
+
+
+    'doubleCross - {
+      val check = new TestEvaluator(
+        doubleCross,
+        Discover[doubleCross.type],
+        pwd / 'target / 'workspace / "cross-tests" / "doubleCross",
+        pwd
+      )
+
+      val Right(("210_jvm", 1)) = check.apply(doubleCross.cross("210", "jvm").suffix)
+      val Right(("210_js", 1)) = check.apply(doubleCross.cross("210", "js").suffix)
+      val Right(("211_jvm", 1)) = check.apply(doubleCross.cross("211", "jvm").suffix)
+      val Right(("211_js", 1)) = check.apply(doubleCross.cross("211", "js").suffix)
+      val Right(("212_jvm", 1)) = check.apply(doubleCross.cross("212", "jvm").suffix)
+      val Right(("212_js", 1)) = check.apply(doubleCross.cross("212", "js").suffix)
+      val Right(("212_native", 1)) = check.apply(doubleCross.cross("212", "native").suffix)
+    }
+
+    'nestedCrosses - {
+      val check = new TestEvaluator(
+        nestedCrosses,
+        Discover[nestedCrosses.type],
+        pwd / 'target / 'workspace / "cross-tests" / "nestedCrosses",
+        pwd
+      )
+
+      val Right(("210_jvm", 1)) = check.apply(nestedCrosses.cross("210").cross2("jvm").suffix)
+      val Right(("210_js", 1)) = check.apply(nestedCrosses.cross("210").cross2("js").suffix)
+      val Right(("211_jvm", 1)) = check.apply(nestedCrosses.cross("211").cross2("jvm").suffix)
+      val Right(("211_js", 1)) = check.apply(nestedCrosses.cross("211").cross2("js").suffix)
+      val Right(("212_jvm", 1)) = check.apply(nestedCrosses.cross("212").cross2("jvm").suffix)
+      val Right(("212_js", 1)) = check.apply(nestedCrosses.cross("212").cross2("js").suffix)
+      val Right(("212_native", 1)) = check.apply(nestedCrosses.cross("212").cross2("native").suffix)
+    }
+  }
+}
diff --git a/core/test/src/mill/util/TestGraphs.scala b/core/test/src/mill/util/TestGraphs.scala
index aa8865ce..581d5e0a 100644
--- a/core/test/src/mill/util/TestGraphs.scala
+++ b/core/test/src/mill/util/TestGraphs.scala
@@ -200,6 +200,24 @@ object TestGraphs{
       def suffix = T{ scalaVersion }
     }
   }
+  object crossResolved extends TestUtil.BaseModule {
+    trait MyModule extends Module{
+      def crossVersion: String
+      implicit object resolver extends mill.define.Cross.Resolver[MyModule]{
+        def resolve[V <: MyModule](c: Cross[V]): V = c.itemMap(List(crossVersion))
+      }
+    }
+
+    object foo extends mill.Cross[FooModule]("2.10", "2.11", "2.12")
+    class FooModule(val crossVersion: String) extends MyModule{
+      def suffix = T{ crossVersion }
+    }
+
+    object bar extends mill.Cross[BarModule]("2.10", "2.11", "2.12")
+    class BarModule(val crossVersion: String) extends MyModule{
+      def longSuffix = T{ "_" + foo().suffix() }
+    }
+  }
   object doubleCross extends TestUtil.BaseModule {
     val crossMatrix = for{
       scalaVersion <- Seq("210", "211", "212")
diff --git a/docs/cross.md b/docs/cross.md
index 9a2bbe92..25ae4a8a 100644
--- a/docs/cross.md
+++ b/docs/cross.md
@@ -139,19 +139,19 @@ to other cross-modules with an identical set of cross values:
 ```scala
 trait MyModule extends Module{
   def crossVersion: String
-  implicit object resolver extends mill.define.Cross.Resolve[ResolvedModule]{
-    def resolve[V <: ResolvedModule](c: Cross[V]): V = c.itemMap(crossVersion)
+  implicit object resolver extends mill.define.Cross.Resolver[MyModule]{
+    def resolve[V <: MyModule](c: Cross[V]): V = c.itemMap(List(crossVersion))
   }
 }
 
 object foo extends mill.Cross[FooModule]("2.10", "2.11", "2.12")
-class FooModule(crossVersion: String) extends MyModule{
+class FooModule(val crossVersion: String) extends MyModule{
   def suffix = T{ crossVersion }
 }
 
 object bar extends mill.Cross[BarModule]("2.10", "2.11", "2.12")
-class BarModule(crossVersion: String) extends MyModule{
-  def bigSuffix = T{ foo().suffix().toUpperCase() }
+class BarModule(val crossVersion: String) extends MyModule{
+  def longSuffix = T{ "_" + foo().suffix() }
 }
 ```