github.com/dolthub/go-mysql-server@v0.18.0/sql/expression/function/aggregation/first_test.go (about)

     1  // Copyright 2020-2021 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package aggregation
    16  
    17  import (
    18  	"testing"
    19  
    20  	"github.com/stretchr/testify/require"
    21  
    22  	"github.com/dolthub/go-mysql-server/sql"
    23  	"github.com/dolthub/go-mysql-server/sql/expression"
    24  	"github.com/dolthub/go-mysql-server/sql/types"
    25  )
    26  
    27  func TestFirst(t *testing.T) {
    28  	testCases := []struct {
    29  		name     string
    30  		rows     []sql.Row
    31  		expected interface{}
    32  	}{
    33  		{"no rows", nil, nil},
    34  		{"one row", []sql.Row{{"first"}}, "first"},
    35  		{"three rows", []sql.Row{{"first"}, {"second"}, {"last"}}, "first"},
    36  	}
    37  
    38  	agg := NewFirst(expression.NewGetField(0, types.Text, "", false))
    39  	for _, tt := range testCases {
    40  		t.Run(tt.name, func(t *testing.T) {
    41  			result := aggregate(t, agg, tt.rows...)
    42  			require.Equal(t, tt.expected, result)
    43  		})
    44  	}
    45  }