Fix nondeterministic test failure in testDependenciesUpdatedSwift

With #1762 we use fallback build settings if the build system doesn’t provide real build systems quickly. This may cause us to initially return empty syntactic diagnostics in this test case, which causes it to fail. Change it to assert that we eventually get the expected semantic diagnostics.

rdar://138913004

Author: ahoppen

Tests/SourceKitLSPTests/DependencyTrackingTests.swift

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import LanguageServerProtocol
+import SKLogging
 import SKTestSupport
 import XCTest
 
@@ -42,18 +43,21 @@ final class DependencyTrackingTests: XCTestCase {
 
     _ = try project.openDocument("LibB.swift")
 
-    let initialDiags = try await project.testClient.nextDiagnosticsNotification()
-    // Semantic analysis: expect module import error.
-    XCTAssertEqual(initialDiags.diagnostics.count, 1)
-    if let diagnostic = initialDiags.diagnostics.first {
+    // Once we have build settings for the file, we should get an error about `LibA` not existing (background
+    // preparation is disabled). Before that, we might get empty syntactic diagnostics.
+    try await repeatUntilExpectedResult {
+      let initialDiags = try? await project.testClient.nextDiagnosticsNotification(timeout: .seconds(1))
       #if compiler(>=6.1)
       #warning("When we drop support for Swift 5.10 we no longer need to check for the Objective-C error message")
       #endif
-      XCTAssert(
+      if let diagnostic = initialDiags?.diagnostics.only,
         diagnostic.message.contains("Could not build Objective-C module")
-          || diagnostic.message.contains("No such module"),
-        "expected module import error but found \"\(diagnostic.message)\""
-      )
+          || diagnostic.message.contains("No such module")
+      {
+        return true
+      }
+      logger.debug("Received unexpected diagnostics: \(initialDiags?.forLogging)")
+      return false
     }
 
     try await SwiftPMTestProject.build(at: project.scratchDirectory)

Tests/SourceKitLSPTests/PublishDiagnosticsTests.swift

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import LanguageServerProtocol
+import SKLogging
 import SKTestSupport
 import XCTest
 
@@ -180,15 +181,22 @@ final class PublishDiagnosticsTests: XCTestCase {
     )
 
     _ = try project.openDocument("LibB.swift")
-    let diagnosticsBeforeBuilding = try await project.testClient.nextDiagnosticsNotification()
-    XCTAssert(
-      diagnosticsBeforeBuilding.diagnostics.contains(where: {
-        #if compiler(>=6.1)
-        #warning("When we drop support for Swift 5.10 we no longer need to check for the Objective-C error message")
-        #endif
+
+    // We might receive empty syntactic diagnostics before getting build settings. Wait until we get the diagnostic
+    // about the missing module.
+    try await repeatUntilExpectedResult {
+      let diagnosticsBeforeBuilding = try? await project.testClient.nextDiagnosticsNotification(timeout: .seconds(1))
+      #if compiler(>=6.1)
+      #warning("When we drop support for Swift 5.10 we no longer need to check for the Objective-C error message")
+      #endif
+      if (diagnosticsBeforeBuilding?.diagnostics ?? []).contains(where: {
         return $0.message == "No such module 'LibA'" || $0.message == "Could not build Objective-C module 'LibA'"
-      })
-    )
+      }) {
+        return true
+      }
+      logger.debug("Received unexpected diagnostics: \(diagnosticsBeforeBuilding?.forLogging)")
+      return false
+    }
 
     try await SwiftPMTestProject.build(at: project.scratchDirectory)
 

Tests/SourceKitLSPTests/PullDiagnosticsTests.swift

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import LanguageServerProtocol
+import SKLogging
 import SKSupport
 import SKTestSupport
 import SourceKitLSP
@@ -204,18 +205,24 @@ final class PullDiagnosticsTests: XCTestCase {
     )
 
     let (bUri, _) = try project.openDocument("LibB.swift")
-    let beforeBuilding = try await project.testClient.send(
-      DocumentDiagnosticsRequest(textDocument: TextDocumentIdentifier(bUri))
-    )
-    XCTAssert(
-      (beforeBuilding.fullReport?.items ?? []).contains(where: {
-        #if compiler(>=6.1)
-        #warning("When we drop support for Swift 5.10 we no longer need to check for the Objective-C error message")
-        #endif
+
+    // We might receive empty syntactic diagnostics before getting build settings. Wait until we get the diagnostic
+    // about the missing module.
+    try await repeatUntilExpectedResult {
+      let beforeBuilding = try? await project.testClient.send(
+        DocumentDiagnosticsRequest(textDocument: TextDocumentIdentifier(bUri))
+      )
+      #if compiler(>=6.1)
+      #warning("When we drop support for Swift 5.10 we no longer need to check for the Objective-C error message")
+      #endif
+      if (beforeBuilding?.fullReport?.items ?? []).contains(where: {
         return $0.message == "No such module 'LibA'" || $0.message == "Could not build Objective-C module 'LibA'"
+      }) {
+        return true
       }
-      )
-    )
+      logger.debug("Received unexpected diagnostics: \(beforeBuilding?.forLogging)")
+      return false
+    }
 
     let diagnosticsRefreshRequestReceived = self.expectation(description: "DiagnosticsRefreshRequest received")
     project.testClient.handleSingleRequest { (request: DiagnosticsRefreshRequest) in