Use #if !canImport(Combine) per test case (as done by @marcprux) and throw an XCTSkip for these test cases. This gives a better impression how many tests are skipped on Linux/non-Darwin platforms.

Author: Tim De Jong

Tests/GRDBTests/DatabaseMigratorTests.swift

@@ -9,8 +9,10 @@ class DatabaseMigratorTests : GRDBTestCase {
         try migrator.migrate(writer)
     }
 
-    #if canImport(Combine)
     func testEmptyMigratorSync() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             let migrator = DatabaseMigrator()
             try migrator.migrate(writer)
@@ -19,9 +21,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testEmptyMigratorAsync() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             let expectation = self.expectation(description: "")
             let migrator = DatabaseMigrator()
@@ -39,9 +45,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testEmptyMigratorPublisher() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             let migrator = DatabaseMigrator()
             let publisher = migrator.migratePublisher(writer)
@@ -52,9 +62,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testNonEmptyMigratorSync() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("createPersons") { db in
@@ -96,9 +110,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testNonEmptyMigratorAsync() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("createPersons") { db in
@@ -147,9 +165,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testNonEmptyMigratorPublisher() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("createPersons") { db in
@@ -199,9 +221,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testEmptyMigratorPublisherIsAsynchronous() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             let migrator = DatabaseMigrator()
             let expectation = self.expectation(description: "")
@@ -221,9 +247,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testNonEmptyMigratorPublisherIsAsynchronous() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("first", migrate: { _ in })
@@ -244,9 +274,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testMigratorPublisherDefaultScheduler() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test<Writer: DatabaseWriter>(writer: Writer) {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("first", migrate: { _ in })
@@ -269,9 +303,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testMigratorPublisherCustomScheduler() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test<Writer: DatabaseWriter>(writer: Writer) {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("first", migrate: { _ in })
@@ -295,9 +333,13 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
     func testMigrateUpTo() throws {
+#if !canImport(Combine)
+        throw XCTSkip("Combine not supported on this platform")
+#else
         func test(writer: some DatabaseWriter) throws {
             var migrator = DatabaseMigrator()
             migrator.registerMigration("a") { db in
@@ -346,9 +388,9 @@ class DatabaseMigratorTests : GRDBTestCase {
         try Test(test).run { try DatabaseQueue() }
         try Test(test).runAtTemporaryDatabasePath { try DatabaseQueue(path: $0) }
         try Test(test).runAtTemporaryDatabasePath { try DatabasePool(path: $0) }
+#endif
     }
 
-    #endif
     func testMigrationFailureTriggersRollback() throws {
         var migrator = DatabaseMigrator()
         migrator.registerMigration("createPersons") { db in