code snippets for "Introduction To Dependency Injection" post

s1.cs

public class SqlMetaDataProvider : IMetaDataProvider
{
    private readonly string _connectionString;
    private readonly SqlDataRetriever _sqlDataRetriever;
  
    public SqlMetaDataProvider(string connectionString)
    {
        _connectionString = connectionString;
        _sqlDataRetriever = new SqlDataRetriever();
    }
  
    public MetaDataStore GetMetaDataStore()
    {
        SqlMetaData sqlMetaData = _sqlDataRetriever.GetMetaData(_connectionString);
 
        return ConvertToMetaDataStore(sqlMetaData);
    }
 
    private MetaDataStore ConvertToMetaDataStore(SqlMetaData sqlMetaData)
    {
        MetaDataStore store = new MetaDataStore();
 
        AddTablesToStore(sqlMetaData.TableInfo, store);
        AddColumnsToTablesInStore(sqlMetaData.ColumnInfo, store);
        CreateRelationshipsBetweenTables(sqlMetaData.RelationshipInfo, store);
 
        return store;
    }
}

s2.cs

public interface ISqlDataRetriever
{
    SqlMetaData GetMetaData(string connectionString);
}

s3.cs

public class SqlDataRetriever : ISqlDataRetriever

s4.cs

private readonly ISqlDataRetriever _sqlDataRetriever;

s5.cs

public SqlMetaDataProvider(string connectionString, ISqlDataRetriever sqlDataRetriever)
{
    _connectionString = connectionString;
    _sqlDataRetriever = sqlDataRetriever;
}

s6.cs

public SqlMetaDataProvider(string connectionString)
        : this(connectionString, new SqlDataRetriever()) {}

s7.cs

public class SqlDataProviderStub : ISqlDataRetriever
{
    private SqlMetaData _sqlMetaData;
 
    public SqlMetaData SqlMetaData
    {
        set { _sqlMetaData = value; }
    }
 
    SqlMetaData ISqlDataRetriever.GetMetaData(string connectionString)
    {
        return _sqlMetaData;
    }
} 

s8.cs

[Test]
public void GetMetaDataStore_ProvideDataSetWithTwoTablesAndRelationship_MetaDataStoreIsCorrect()
{
    SqlMetaData sqlMetaData = PrepareMetaDataSetInMemoryWithTestData();
 
    SqlDataProviderStub sqlDataProvider = new SqlDataProviderStub();
    sqlDataProvider.SqlMetaData = sqlMetaData;
 
    // pass null as the connectionString, and pass our SqlDataProviderStub
    IMetaDataProvider metaDataProvider = new SqlMetaDataProvider(null, sqlDataProvider);
 
    MetaDataStore store = metaDataProvider.GetMetaDataStore();
 
    AssertStoreContainsOurTestData(store);
}