Fix assertQuery changing to empty results after snapshot contains results

[rcarver]

Fixes the issue brought up in slack

[stephencelis]

@rcarver Can you give an example of what this fixes? Maybe a test with an expected failure or something to that effect?

I think the fix we probably want to apply here is to always record an empty result set, something like:

assertQuery(Reminder.all) {
  """
  (No results.)
  """
}

Think you could cook that change up?

[rcarver]

@stephencelis sorry based on the comments in slack I assumed you'd have context. This fixes the following:

1. Successfully record a snapshot of some results
2. Change the database content such that no results are returned
3. Run the test again, it continues to pass when it should fail ("no results")

Here's a diff I used to switch between .database() and .emptyDatabase() to confirm that the test fails as expected.

diff --git a/Tests/SharingGRDBTests/AssertQueryTests.swift b/Tests/SharingGRDBTests/AssertQueryTests.swift
index 73de34d..6dbe543 100644
--- a/Tests/SharingGRDBTests/AssertQueryTests.swift
+++ b/Tests/SharingGRDBTests/AssertQueryTests.swift
@@ -153,4 +153,40 @@ extension DatabaseWriter where Self == DatabaseQueue {
     }
     return database
   }
+  fileprivate static func emptyDatabase() throws -> DatabaseQueue {
+    let database = try DatabaseQueue()
+    try database.write { db in
+      try #sql(
+        """
+        CREATE TABLE "records" (
+          "id" INTEGER PRIMARY KEY AUTOINCREMENT,
+          "date" INTEGER NOT NULL DEFAULT 42
+        )
+        """
+      )
+      .execute(db)
+    }
+    return database
+  }
+}
+
+
+@Suite(
+  .dependency(\.defaultDatabase, try .database()),
+  .snapshots(record: .failed),
+)
+struct AssertQueryEmptyResultTests {
+  @Test func assertQueryBasic() throws {
+    assertQuery(
+      Record.all.select(\.id)
+    ) {
+      """
+      ┌───┐
+      │ 1 │
+      │ 2 │
+      │ 3 │
+      └───┘
+      """
+    }
+  }
 }

[rcarver]

Also clarified the 'no results' case

  @Test func assertQueryEmpty() throws {
    assertQuery(
      Record.all.where { $0.id == -1 }.select(\.id)
    ) {
      """
      (No results)
      """
    }
  }

[rcarver]

Hmm, looks like this got caught in the repo rename, let me know if you'd like me to recreate the PR

[mbrandonw]

I just merged main to get everything caught up and re-recorded the SQLiteData tests which now properly shows "(no results)" in a bunch of tests.

[rcarver]

Thanks! lgtm

[acosmicflamingo]

Looks good to me too!