You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: dgelqf.go
    path of file: ./repos/gonum/lapack/testlapack
    
    the code of the file until where you have to start completion: // Copyright ©2015 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package testlapack

import (
	"testing"

	"golang.org/x/exp/rand"

	"gonum.org/v1/gonum/floats"
)

type Dgelqfer interface {
	Dgelq2er
	Dgelqf(m, n int, a []float64, lda int, tau, work []float64, lwork int)
}

func DgelqfTest(t *testing.T, impl Dgelqfer) {
	const t
    
func DgelqfTest(t *testing.T, impl Dgelqfer) {
	const tol = 1e-12
	rnd := rand.New(rand.NewSource(1))
	for c, test := range []struct {
		m, n, lda int
	}{
		{10, 5, 0},
		{5, 10, 0},
		{10, 10, 0},
		{300, 5, 0},
		{3, 500, 0},
		{200, 200, 0},
		{300, 200, 0},
		{204, 300, 0},
		{1, 3000, 0},
		{3000, 1, 0},
		{10, 5, 30},
		{5, 10, 30},
		{10, 10, 30},
		{300, 5, 500},
		{3, 500, 600},
		{200, 200, 300},
		{300, 200, 300},
		{204, 300, 400},
		{1, 3000, 4000},
		{3000, 1, 4000},
	} {
		m := test.m
		n := test.n
		lda := test.lda
		if lda == 0 {
			lda = n
		}
		// Allocate m×n matrix A and fill it with random numbers.
		a := make([]float64, m*lda)
		for i := range a {
			a[i] = rnd.NormFloat64()
		}
		// Store a copy of A for later comparison.
		aCopy := make([]float64, len(a))
		copy(aCopy, a)

		// Allocate a slice for scalar factors of elementary reflectors
		// and fill it with random numbers.
		tau := make([]float64, n)
		for i := 0; i < n; i++ {
			tau[i] = rnd.NormFloat64()
		}

		// Compute the expected result using unblocked LQ algorithm and
		// store it want.
		want := make([]float64, len(a))
		copy(want, a)
		impl.Dgelq2(m, n, want, lda, tau, make([]float64, m))

		for _, wl := range []worklen{minimumWork, mediumWork, optimumWork} {
			copy(a, aCopy)

			var lwork int
			switch wl {
			case minimumWork:
				lwork = m
			case mediumWork:
				work := make([]float64, 1)
				impl.Dgelqf(m, n, a, lda, tau, work, -1)
				lwork = int(work[0]) - 2*m
			case optimumWork:
				work := make([]float64, 1)
				impl.Dgelqf(m, n, a, lda, tau, work, -1)
				lwork = int(work[0])
			}
			work := make([]float64, lwork)

			// Compute the LQ factorization of A.
			impl.Dgelqf(m, n, a, lda, tau, work, len(work))
			// Compare the result with Dgelq2.
			if !floats.EqualApprox(want, a, tol) {
				t.Errorf("Case %v, workspace type %v, unexpected result", c, wl)
			}
		}
	}
}