IDE: add test infrastructure for diagnostics

Author: smarter

language-server/test/dotty/tools/languageserver/DiagnosticsTest.scala

@@ -0,0 +1,18 @@
+package dotty.tools.languageserver
+
+import org.junit.Test
+
+import dotty.tools.dotc.reporting.diagnostic.ErrorMessageID._
+import dotty.tools.languageserver.util.Code._
+import org.eclipse.lsp4j.DiagnosticSeverity._
+
+class DiagnosticsTest {
+  @Test def diagnosticWrongType: Unit =
+    code"""object Test {
+          |  val x: Int = $m1"foo"$m2
+          |}""".withSource
+      .diagnostics(m1,
+        (m1 to m2, """found:    String("foo")
+                     |required: Int""".stripMargin, Error, Some(TypeMismatchID))
+      )
+}

language-server/test/dotty/tools/languageserver/util/CodeRange.scala

@@ -19,7 +19,7 @@ case class CodeRange(start: CodeMarker, end: CodeMarker) {
     if (!checked) {
       assert(start.file == end.file, s"$start and $end where not in the same file")
       assert(start.line <= end.line, s"Expected $end to be after $start")
-      assert(start.line != end.line || start.character < end.character, s"Expected $end to be after $start")
+      assert(start.line != end.line || start.character <= end.character, s"Expected $end to be at or after $start")
       checked = true
     }
   }

language-server/test/dotty/tools/languageserver/util/CodeTester.scala

@@ -5,9 +5,12 @@ import dotty.tools.languageserver.util.actions._
 import dotty.tools.languageserver.util.embedded.CodeMarker
 import dotty.tools.languageserver.util.server.{TestFile, TestServer}
 
+import dotty.tools.dotc.reporting.diagnostic.ErrorMessageID
 import dotty.tools.dotc.util.Signatures.Signature
 
-import org.eclipse.lsp4j.{CompletionItemKind, DocumentHighlightKind}
+import org.eclipse.lsp4j.{ CompletionItemKind, DocumentHighlightKind, Diagnostic, DiagnosticSeverity }
+
+import org.junit.Assert.assertEquals
 
 /**
  * Simulates an LSP client for test in a project defined by `sources`.
@@ -30,6 +33,32 @@ class CodeTester(projects: List[Project]) {
 
   private val positions: PositionContext = getPositions(files)
 
+  /** Check that the last diagnostics that have been published so far by the server
+   *  for a given file match `expected`.
+   *
+   * @param marker   The marker defining the source file from which to query.
+   * @param expected The expected diagnostics to be found
+   */
+  def diagnostics(marker: CodeMarker,
+      expected: (CodeRange, String, DiagnosticSeverity, Option[ErrorMessageID])*): this.type = {
+    implicit val posCtx = positions
+
+    def toDiagnostic(range: CodeRange, message: String, severity: DiagnosticSeverity,
+        errorCode: Option[ErrorMessageID]): Diagnostic = {
+      val location = range.toLocation
+      new Diagnostic(
+        location.getRange, message, severity, /*source=*/"", errorCode.map(_.errorNumber.toString).getOrElse(null)
+      )
+    }
+
+    val expectedParams = marker.toPublishDiagnosticsParams(expected.toList.map(toDiagnostic))
+    val actualParams = testServer.client.diagnostics.get.reverse.find(_.getUri == marker.uri)
+      .getOrElse(throw new Exception(s"No published diagnostics for ${marker.uri}"))
+    assertEquals(expectedParams, actualParams)
+
+    this
+  }
+
   /**
    * Perform a hover over `range`, verifies that result matches `expected`.
    *

language-server/test/dotty/tools/languageserver/util/embedded/CodeMarker.scala

@@ -3,6 +3,8 @@ package dotty.tools.languageserver.util.embedded
 import dotty.tools.languageserver.util.server.TestFile
 import dotty.tools.languageserver.util.{CodeRange, PositionContext}
 
+import scala.collection.JavaConverters._
+
 import org.eclipse.lsp4j._
 
 import PositionContext.PosCtx
@@ -16,6 +18,9 @@ class CodeMarker(val name: String) extends Embedded {
   /** The file containing this marker. */
   def file: PosCtx[TestFile] = posCtx.positionOf(this)._1
 
+  /** The uri of the file containing this marker. */
+  def uri: PosCtx[String] = file.uri
+
   /** The line containing this marker. */
   def line: PosCtx[Int] = posCtx.positionOf(this)._2
 
@@ -34,6 +39,9 @@ class CodeMarker(val name: String) extends Embedded {
   def toCompletionParams: PosCtx[CompletionParams] =
     new CompletionParams(toTextDocumentIdentifier, toPosition)
 
+  def toPublishDiagnosticsParams(diagnostics: List[Diagnostic]): PosCtx[PublishDiagnosticsParams] =
+    new PublishDiagnosticsParams(file.uri, diagnostics.asJava)
+
   def toRenameParams(newName: String): PosCtx[RenameParams] =
     new RenameParams(toTextDocumentIdentifier, toPosition, newName)