Initial import with skill sheet working

node_modules/abstract-level/test/iterator-no-snapshot-test.js

@@ -0,0 +1,63 @@
+'use strict'
+
+exports.noSnapshot = function (test, testCommon) {
+  function make (run) {
+    return function (t) {
+      const db = testCommon.factory()
+      const operations = [
+        { type: 'put', key: 'a', value: 'a' },
+        { type: 'put', key: 'b', value: 'b' },
+        { type: 'put', key: 'c', value: 'c' }
+      ]
+
+      db.open(function (err) {
+        t.ifError(err, 'no open error')
+
+        db.batch(operations, function (err) {
+          t.ifError(err, 'no batch error')
+
+          // For this test it is important that we don't read eagerly.
+          // NOTE: highWaterMarkBytes is not an abstract option, but
+          // it is supported by classic-level and others. Also set the
+          // old & equivalent leveldown highWaterMark option for compat.
+          const it = db.iterator({ highWaterMarkBytes: 0, highWaterMark: 0 })
+
+          run(db, function (err) {
+            t.ifError(err, 'no run error')
+            verify(t, it, db)
+          })
+        })
+      })
+    }
+  }
+
+  function verify (t, it, db) {
+    it.all(function (err, entries) {
+      t.ifError(err, 'no iterator error')
+
+      const kv = entries.map(function ([key, value]) {
+        return key.toString() + value.toString()
+      })
+
+      if (kv.length === 3) {
+        t.same(kv, ['aa', 'bb', 'cc'], 'maybe supports snapshots')
+      } else {
+        t.same(kv, ['aa', 'cc'], 'ignores keys that have been deleted in the mean time')
+      }
+
+      db.close(t.end.bind(t))
+    })
+  }
+
+  test('delete key after creating iterator', make(function (db, done) {
+    db.del('b', done)
+  }))
+
+  test('batch delete key after creating iterator', make(function (db, done) {
+    db.batch([{ type: 'del', key: 'b' }], done)
+  }))
+}
+
+exports.all = function (test, testCommon) {
+  exports.noSnapshot(test, testCommon)
+}