Add test for int setting

Author: som-snytt

compiler/test/dotty/tools/dotc/SettingsTests.scala

@@ -166,18 +166,23 @@ class SettingsTests {
       )
       assertEquals(expectedErrors, summary.errors)
     }
+  end validateChoices
 
   @Test def `Allow IntSetting's to be set with a colon`: Unit =
     object Settings extends SettingGroup:
       val foo = IntSetting("-foo", "foo", 80)
     import Settings._
 
-    val args = List("-foo:100")
-    val summary = processArguments(args, processAll = true)
-    assertTrue(s"Setting args errors:\n  ${summary.errors.take(5).mkString("\n  ")}", summary.errors.isEmpty)
-    withProcessedArgs(summary) {
-      assertEquals(100, foo.value)
+    def check(args: List[String]) = {
+      val summary = processArguments(args, processAll = true)
+      assertTrue(s"Setting args errors:\n  ${summary.errors.take(5).mkString("\n  ")}", summary.errors.isEmpty)
+      withProcessedArgs(summary) {
+        assertEquals(100, foo.value)
+      }
     }
+    check(List("-foo:100"))
+    check(List("-foo", "100"))
+    assertThrows[AssertionError](_.getMessage.contains("missing argument for option -foo"))(check(List("-foo")))
 
   private def withProcessedArgs(summary: ArgsSummary)(f: SettingsState ?=> Unit) = f(using summary.sstate)