diff --git a/blas/testblas/dtrsm.go b/blas/testblas/dtrsm.go
index d5ec6258a6..47c49e056a 100644
--- a/blas/testblas/dtrsm.go
+++ b/blas/testblas/dtrsm.go
@@ -7,6 +7,7 @@ package testblas
 import (
 	"testing"
 
+	"golang.org/x/exp/rand"
 	"gonum.org/v1/gonum/blas"
 	"gonum.org/v1/gonum/floats"
 )
@@ -16,7 +17,8 @@ type Dtrsmer interface {
 		alpha float64, a []float64, lda int, b []float64, ldb int)
 }
 
-func DtrsmTest(t *testing.T, blasser Dtrsmer) {
+func DtrsmTest(t *testing.T, impl Dtrsmer) {
+	rnd := rand.New(rand.NewSource(1))
 	for i, test := range []struct {
 		s     blas.Side
 		ul    blas.Uplo
@@ -27,7 +29,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 		alpha float64
 		a     [][]float64
 		b     [][]float64
-		ans   [][]float64
+		want  [][]float64
 	}{
 		{
 			s:     blas.Left,
@@ -47,7 +49,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{1, 3.4},
 				{-0.5, -0.5},
 				{2, 3.2},
@@ -71,7 +73,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{60, 96},
 				{-42, -66},
 				{10, 16},
@@ -95,7 +97,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 1, 3},
 				{5, 8, 9, 10},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{1, 3.4, 1.2, 13},
 				{-0.5, -0.5, -4, -3.5},
 				{2, 3.2, 3.6, 4},
@@ -119,7 +121,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 1, 3},
 				{5, 8, 9, 10},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{60, 96, 126, 146},
 				{-42, -66, -88, -94},
 				{10, 16, 18, 20},
@@ -143,7 +145,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.5, 9},
 				{-0.375, -1.5},
 				{-0.75, -12.0 / 7},
@@ -167,7 +169,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{9, 18},
 				{-15, -33},
 				{60, 132},
@@ -191,7 +193,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 1, 3},
 				{5, 8, 9, 10},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.5, 9, 3, 13.5},
 				{-0.375, -1.5, -1.5, -63.0 / 8},
 				{-0.75, -12.0 / 7, 3, 39.0 / 28},
@@ -215,7 +217,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 1, 3},
 				{5, 8, 9, 10},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{9, 18, 6, 27},
 				{-15, -33, -15, -72},
 				{60, 132, 87, 327},
@@ -239,7 +241,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.5, 9},
 				{-0.30, -1.2},
 				{-6.0 / 35, -24.0 / 35},
@@ -263,7 +265,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{9, 18},
 				{-15, -33},
 				{69, 150},
@@ -287,7 +289,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 8, 9},
 				{5, 8, 10, 11},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.5, 9, 9, 10.5},
 				{-0.3, -1.2, -0.6, -0.9},
 				{-6.0 / 35, -24.0 / 35, -12.0 / 35, -18.0 / 35},
@@ -311,7 +313,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 8, 9},
 				{5, 8, 10, 11},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{9, 18, 18, 21},
 				{-15, -33, -30, -36},
 				{69, 150, 138, 165},
@@ -335,7 +337,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{-0.46875, 0.375},
 				{0.1875, 0.75},
 				{1.875, 3},
@@ -359,7 +361,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7},
 				{5, 8},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{168, 267},
 				{-78, -123},
 				{15, 24},
@@ -383,7 +385,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 4, 5},
 				{5, 8, 6, 7},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{-0.46875, 0.375, -2.0625, -1.78125},
 				{0.1875, 0.75, -0.375, -0.1875},
 				{1.875, 3, 2.25, 2.625},
@@ -407,7 +409,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{4, 7, 4, 5},
 				{5, 8, 6, 7},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{168, 267, 204, 237},
 				{-78, -123, -96, -111},
 				{15, 24, 18, 21},
@@ -432,7 +434,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{15, -2.4, -48.0 / 35},
 				{19.5, -3.3, -66.0 / 35},
 				{24, -4.2, -2.4},
@@ -458,7 +460,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{30, -57, 258},
 				{39, -75, 339},
 				{48, -93, 420},
@@ -482,7 +484,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{15, -2.4, -48.0 / 35},
 				{19.5, -3.3, -66.0 / 35},
 			},
@@ -504,7 +506,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{30, -57, 258},
 				{39, -75, 339},
 			},
@@ -528,7 +530,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.2, 1.2, 4.5},
 				{5.775, 1.65, 5.625},
 				{7.35, 2.1, 6.75},
@@ -554,7 +556,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{435, -183, 36},
 				{543, -228, 45},
 				{651, -273, 54},
@@ -578,7 +580,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.2, 1.2, 4.5},
 				{5.775, 1.65, 5.625},
 			},
@@ -600,7 +602,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{435, -183, 36},
 				{543, -228, 45},
 			},
@@ -624,7 +626,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.2, 1.2, 4.5},
 				{5.775, 1.65, 5.625},
 				{7.35, 2.1, 6.75},
@@ -650,7 +652,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{435, -183, 36},
 				{543, -228, 45},
 				{651, -273, 54},
@@ -674,7 +676,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{4.2, 1.2, 4.5},
 				{5.775, 1.65, 5.625},
 			},
@@ -696,7 +698,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{435, -183, 36},
 				{543, -228, 45},
 			},
@@ -720,7 +722,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{15, -2.4, -1.2},
 				{19.5, -3.3, -1.65},
 				{24, -4.2, -2.1},
@@ -746,7 +748,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{16, 17, 18},
 				{19, 20, 21},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{30, -57, 258},
 				{39, -75, 339},
 				{48, -93, 420},
@@ -770,7 +772,7 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{15, -2.4, -1.2},
 				{19.5, -3.3, -1.65},
 			},
@@ -792,24 +794,75 @@ func DtrsmTest(t *testing.T, blasser Dtrsmer) {
 				{10, 11, 12},
 				{13, 14, 15},
 			},
-			ans: [][]float64{
+			want: [][]float64{
 				{30, -57, 258},
 				{39, -75, 339},
 			},
 		},
+		{
+			s:     blas.Right,
+			ul:    blas.Lower,
+			tA:    blas.Trans,
+			d:     blas.Unit,
+			m:     2,
+			n:     3,
+			alpha: 0,
+			a: [][]float64{
+				{2, 0, 0},
+				{3, 5, 0},
+				{4, 6, 8},
+			},
+			b: [][]float64{
+				{10, 11, 12},
+				{13, 14, 15},
+			},
+			want: [][]float64{
+				{0, 0, 0},
+				{0, 0, 0},
+			},
+		},
 	} {
-		aFlat := flatten(test.a)
-		bFlat := flatten(test.b)
-		ansFlat := flatten(test.ans)
-		var lda int
-		if test.s == blas.Left {
-			lda = test.m
-		} else {
-			lda = test.n
+		m := test.m
+		n := test.n
+		na := m
+		if test.s == blas.Right {
+			na = n
 		}
-		blasser.Dtrsm(test.s, test.ul, test.tA, test.d, test.m, test.n, test.alpha, aFlat, lda, bFlat, test.n)
-		if !floats.EqualApprox(ansFlat, bFlat, 1e-13) {
-			t.Errorf("Case %v: Want %v, got %v.", i, ansFlat, bFlat)
+		for _, lda := range []int{na, na + 3} {
+			for _, ldb := range []int{n, n + 5} {
+				a := make([]float64, na*lda)
+				for i := range a {
+					a[i] = rnd.NormFloat64()
+				}
+				for i := 0; i < na; i++ {
+					for j := 0; j < na; j++ {
+						a[i*lda+j] = test.a[i][j]
+					}
+				}
+
+				b := make([]float64, m*ldb)
+				for i := range b {
+					b[i] = rnd.NormFloat64()
+				}
+				for i := 0; i < m; i++ {
+					for j := 0; j < n; j++ {
+						b[i*ldb+j] = test.b[i][j]
+					}
+				}
+
+				impl.Dtrsm(test.s, test.ul, test.tA, test.d, test.m, test.n, test.alpha, a, lda, b, ldb)
+
+				want := make([]float64, len(b))
+				copy(want, b)
+				for i := 0; i < m; i++ {
+					for j := 0; j < n; j++ {
+						want[i*ldb+j] = test.want[i][j]
+					}
+				}
+				if !floats.EqualApprox(want, b, 1e-13) {
+					t.Errorf("Case %v: Want %v, got %v.", i, want, b)
+				}
+			}
 		}
 	}
 }