public async Task MaintainWillCreateAliasesOnTimeSeriesIndex() {
            SystemClock.SetFixedTime(SystemClock.UtcNow);
            var version1Index = new DailyEmployeeIndex(_configuration, 1);
            await version1Index.DeleteAsync();

            var version2Index = new DailyEmployeeIndex(_configuration, 2);
            await version2Index.DeleteAsync();

            // Indexes don't exist yet so the current version will be the index version.
            Assert.Equal(1, await version1Index.GetCurrentVersionAsync());
            Assert.Equal(2, await version2Index.GetCurrentVersionAsync());

            using (new DisposableAction(() => version1Index.DeleteAsync().GetAwaiter().GetResult())) {
                await version1Index.ConfigureAsync();
                await version1Index.EnsureIndexAsync(SystemClock.UtcNow);
                Assert.True(_client.IndexExists(version1Index.GetVersionedIndex(SystemClock.UtcNow)).Exists);
                Assert.Equal(1, await version1Index.GetCurrentVersionAsync());

                // delete all aliases
                await _configuration.Cache.RemoveAllAsync();
                await DeleteAliases(version1Index.GetVersionedIndex(SystemClock.UtcNow));

                using (new DisposableAction(() => version2Index.DeleteAsync().GetAwaiter().GetResult())) {
                    await version2Index.ConfigureAsync();
                    await version2Index.EnsureIndexAsync(SystemClock.UtcNow);
                    Assert.True(_client.IndexExists(version2Index.GetVersionedIndex(SystemClock.UtcNow)).Exists);
                    Assert.Equal(2, await version2Index.GetCurrentVersionAsync());

                    // delete all aliases
                    await _configuration.Cache.RemoveAllAsync();
                    await DeleteAliases(version2Index.GetVersionedIndex(SystemClock.UtcNow));

                    await _client.RefreshAsync();
                    var aliasesResponse = await _client.GetAliasesAsync(a => a.Indices(version1Index.GetVersionedIndex(SystemClock.UtcNow), version2Index.GetVersionedIndex(SystemClock.UtcNow)));
                    Assert.Equal(0, aliasesResponse.Indices.SelectMany(i => i.Value).Count());

                    // Indexes exist but no alias so the oldest index version will be used.
                    Assert.Equal(1, await version1Index.GetCurrentVersionAsync());
                    Assert.Equal(1, await version2Index.GetCurrentVersionAsync());

                    await version1Index.MaintainAsync();
                    aliasesResponse = await _client.GetAliasesAsync(a => a.Indices(version1Index.GetVersionedIndex(SystemClock.UtcNow)));
                    Assert.Equal(version1Index.Aliases.Count + 1, aliasesResponse.Indices.Single().Value.Count);
                    aliasesResponse = await _client.GetAliasesAsync(a => a.Indices(version2Index.GetVersionedIndex(SystemClock.UtcNow)));
                    Assert.Equal(0, aliasesResponse.Indices.Single().Value.Count);

                    Assert.Equal(1, await version1Index.GetCurrentVersionAsync());
                    Assert.Equal(1, await version2Index.GetCurrentVersionAsync());
                }
            }
        }
        public async Task DailyIndexMaxAge(DateTime utcNow) {
            SystemClock.SetFixedTime(utcNow);

            var index = new DailyEmployeeIndex(_configuration, 1);
            index.MaxIndexAge = TimeSpan.FromDays(1);
            await index.DeleteAsync();

            using (new DisposableAction(() => index.DeleteAsync().GetAwaiter().GetResult())) {
                await index.ConfigureAsync();
                
                await index.EnsureIndexAsync(utcNow);
                var existsResponse = await _client.IndexExistsAsync(index.GetIndex(utcNow));
                _logger.Trace(() => existsResponse.GetRequest());
                Assert.True(existsResponse.IsValid);
                Assert.True(existsResponse.Exists);

                await index.EnsureIndexAsync(utcNow.SubtractDays(1));
                existsResponse = await _client.IndexExistsAsync(index.GetIndex(utcNow.SubtractDays(1)));
                _logger.Trace(() => existsResponse.GetRequest());
                Assert.True(existsResponse.IsValid);
                Assert.True(existsResponse.Exists);

                await Assert.ThrowsAsync<ArgumentException>(async () => await index.EnsureIndexAsync(utcNow.SubtractDays(2)));
                existsResponse = await _client.IndexExistsAsync(index.GetIndex(utcNow.SubtractDays(2)));
                _logger.Trace(() => existsResponse.GetRequest());
                Assert.True(existsResponse.IsValid);
                Assert.False(existsResponse.Exists);
            }
        }