Test to verify changing dylib opening behavior

moor_ffi/lib/src/load_library.dart

@@ -1,6 +1,8 @@
 import 'dart:ffi';
 import 'dart:io';
 
+import 'package:meta/meta.dart';
+
 /// Signature responsible for loading the dynamic sqlite3 library that moor will
 /// use.
 typedef OpenLibrary = DynamicLibrary Function();
@@ -90,6 +92,7 @@ class OpenDynamicLibrary {
     _overriddenPlatforms[os] = open;
   }
 
+  // ignore: use_setters_to_change_properties
   /// Makes `moor_ffi` use the [OpenLibrary] function for all Dart platforms.
   /// If this method has been called, it takes precedence over [overrideFor].
   /// This method must be called before opening any database.
@@ -99,4 +102,11 @@ class OpenDynamicLibrary {
   void overrideForAll(OpenLibrary open) {
     _overriddenForAll = open;
   }
+
+  /// Clears all associated open helpers for all platforms.
+  @visibleForTesting
+  void reset() {
+    _overriddenForAll = null;
+    _overriddenPlatforms.clear();
+  }
 }

moor_ffi/pubspec.yaml

@@ -11,6 +11,7 @@ dependencies:
   moor: ">=1.7.0 <3.0.0"
   ffi: ^0.1.3
   collection: ^1.0.0
+  meta: ^1.0.2
 
 dev_dependencies:
   test: ^1.6.0

moor_ffi/test/load_library_test.dart

@@ -0,0 +1,17 @@
+import 'package:test/test.dart';
+import 'package:moor_ffi/open_helper.dart';
+
+void main() {
+  tearDown(open.reset);
+
+  test('opening behavior can be overridden', () {
+    var called = false;
+    open.overrideFor(open.os, () {
+      called = true;
+      return null;
+    });
+
+    expect(open.openSqlite(), isNull);
+    expect(called, isTrue);
+  });
+}