all: make tests pass when -count is greater than 1

Tests run repeatedly do not reinitialise state, meaning that a second run
of the tests will have leftover state from the previous run. This ensures
that repeated runs are identical with the exception of map iteration order.

graph/graph_test.go

@@ -17,7 +17,8 @@ type graphBuilder interface {
 	graph.Builder
 }
 
-var copyTests = []struct {
+func TestCopy(t *testing.T) {
+	copyTests := []struct {
 		desc string
 
 		src graph.Graph
@@ -25,7 +26,7 @@ var copyTests = []struct {
 
 		// If want is nil, compare to src.
 		want graph.Graph
-}{
+	}{
 		{
 			desc: "undirected to undirected",
 			src: func() graph.Graph {
@@ -121,9 +122,8 @@ var copyTests = []struct {
 			}(),
 			dst: simple.NewDirectedGraph(),
 		},
-}
+	}
 
-func TestCopy(t *testing.T) {
 	for _, test := range copyTests {
 		graph.Copy(test.dst, test.src)
 		want := test.want
@@ -141,7 +141,8 @@ type graphWeightedBuilder interface {
 	graph.WeightedBuilder
 }
 
-var copyWeightedTests = []struct {
+func TestCopyWeighted(t *testing.T) {
+	copyWeightedTests := []struct {
 		desc string
 
 		src graph.Weighted
@@ -149,7 +150,7 @@ var copyWeightedTests = []struct {
 
 		// If want is nil, compare to src.
 		want graph.Graph
-}{
+	}{
 		{
 			desc: "undirected to undirected",
 			src: func() graph.Weighted {
@@ -245,9 +246,8 @@ var copyWeightedTests = []struct {
 			}(),
 			dst: simple.NewWeightedDirectedGraph(0, 0),
 		},
-}
+	}
 
-func TestCopyWeighted(t *testing.T) {
 	for _, test := range copyWeightedTests {
 		graph.CopyWeighted(test.dst, test.src)
 		want := test.want

graph/layout/eades_test.go

@@ -19,12 +19,13 @@ import (
 	. "gonum.org/v1/gonum/graph/layout"
 )
 
-var eadesR2Tests = []struct {
+func TestEadesR2(t *testing.T) {
+	eadesR2Tests := []struct {
 		name      string
 		g         graph.Graph
 		param     EadesR2
 		wantIters int
-}{
+	}{
 		{
 			name: "line",
 			g: func() graph.Graph {
@@ -194,9 +195,8 @@ var eadesR2Tests = []struct {
 			param:     EadesR2{Repulsion: 1, Rate: 0.1, Updates: 100, Theta: 0.1, Src: rand.NewSource(1)},
 			wantIters: 100,
 		},
-}
+	}
 
-func TestEadesR2(t *testing.T) {
 	for _, test := range eadesR2Tests {
 		eades := test.param
 		o := NewOptimizerR2(test.g, eades.Update)

graph/layout/isomap_test.go

@@ -28,10 +28,11 @@ var (
 	arch string
 )
 
-var isomapR2Tests = []struct {
+func TestIsomapR2(t *testing.T) {
+	isomapR2Tests := []struct {
 		name string
 		g    graph.Graph
-}{
+	}{
 		{
 			name: "line_isomap",
 			g: func() graph.Graph {
@@ -157,9 +158,8 @@ var isomapR2Tests = []struct {
 				return orderedGraph{g}
 			}(),
 		},
-}
+	}
 
-func TestIsomapR2(t *testing.T) {
 	for _, test := range isomapR2Tests {
 		o := NewOptimizerR2(test.g, IsomapR2{}.Update)
 		var n int

graph/nodes_edges_test.go

@@ -21,11 +21,16 @@ import (
 // weightedlines
 // empty
 
-var nodesOfTests = []struct {
+type basicNodes struct {
+	graph.Nodes
+}
+
+func TestNodesOf(t *testing.T) {
+	nodesOfTests := []struct {
 		name  string
 		nodes graph.Nodes
 		want  []graph.Node
-}{
+	}{
 		{
 			name:  "nil",
 			nodes: nil,
@@ -56,13 +61,8 @@ var nodesOfTests = []struct {
 			nodes: iterator.NewOrderedNodes([]graph.Node{simple.Node(-1), simple.Node(0), simple.Node(1), simple.Node(2), simple.Node(3)}),
 			want:  []graph.Node{simple.Node(-1), simple.Node(0), simple.Node(1), simple.Node(2), simple.Node(3)},
 		},
-}
+	}
 
-type basicNodes struct {
-	graph.Nodes
-}
-
-func TestNodesOf(t *testing.T) {
 	for _, test := range nodesOfTests {
 		got := graph.NodesOf(test.nodes)
 		if !reflect.DeepEqual(got, test.want) {
@@ -71,11 +71,16 @@ func TestNodesOf(t *testing.T) {
 	}
 }
 
-var edgesOfTests = []struct {
+type basicEdges struct {
+	graph.Edges
+}
+
+func TestEdgesOf(t *testing.T) {
+	edgesOfTests := []struct {
 		name  string
 		edges graph.Edges
 		want  []graph.Edge
-}{
+	}{
 		{
 			name:  "nil",
 			edges: nil,
@@ -117,13 +122,8 @@ var edgesOfTests = []struct {
 				simple.Edge{F: simple.Node(3), T: simple.Node(4)},
 			},
 		},
-}
+	}
 
-type basicEdges struct {
-	graph.Edges
-}
-
-func TestEdgesOf(t *testing.T) {
 	for _, test := range edgesOfTests {
 		got := graph.EdgesOf(test.edges)
 		if !reflect.DeepEqual(got, test.want) {
@@ -132,11 +132,16 @@ func TestEdgesOf(t *testing.T) {
 	}
 }
 
-var weightedEdgesOfTests = []struct {
+type basicWeightedEdges struct {
+	graph.WeightedEdges
+}
+
+func TestWeightedEdgesOf(t *testing.T) {
+	weightedEdgesOfTests := []struct {
 		name  string
 		edges graph.WeightedEdges
 		want  []graph.WeightedEdge
-}{
+	}{
 		{
 			name:  "nil",
 			edges: nil,
@@ -178,13 +183,8 @@ var weightedEdgesOfTests = []struct {
 				simple.WeightedEdge{F: simple.Node(3), T: simple.Node(4), W: 3},
 			},
 		},
-}
+	}
 
-type basicWeightedEdges struct {
-	graph.WeightedEdges
-}
-
-func TestWeightedEdgesOf(t *testing.T) {
 	for _, test := range weightedEdgesOfTests {
 		got := graph.WeightedEdgesOf(test.edges)
 		if !reflect.DeepEqual(got, test.want) {
@@ -193,11 +193,16 @@ func TestWeightedEdgesOf(t *testing.T) {
 	}
 }
 
-var linesOfTests = []struct {
+type basicLines struct {
+	graph.Lines
+}
+
+func TestLinesOf(t *testing.T) {
+	linesOfTests := []struct {
 		name  string
 		lines graph.Lines
 		want  []graph.Line
-}{
+	}{
 		{
 			name:  "nil",
 			lines: nil,
@@ -239,13 +244,8 @@ var linesOfTests = []struct {
 				multi.Line{F: multi.Node(3), T: multi.Node(4), UID: 1},
 			},
 		},
-}
+	}
 
-type basicLines struct {
-	graph.Lines
-}
-
-func TestLinesOf(t *testing.T) {
 	for _, test := range linesOfTests {
 		got := graph.LinesOf(test.lines)
 		if !reflect.DeepEqual(got, test.want) {
@@ -254,11 +254,16 @@ func TestLinesOf(t *testing.T) {
 	}
 }
 
-var weightedLinesOfTests = []struct {
+type basicWeightedLines struct {
+	graph.WeightedLines
+}
+
+func TestWeightedLinesOf(t *testing.T) {
+	weightedLinesOfTests := []struct {
 		name  string
 		lines graph.WeightedLines
 		want  []graph.WeightedLine
-}{
+	}{
 		{
 			name:  "nil",
 			lines: nil,
@@ -300,13 +305,8 @@ var weightedLinesOfTests = []struct {
 				multi.WeightedLine{F: multi.Node(3), T: multi.Node(4), W: 3, UID: 1},
 			},
 		},
-}
+	}
 
-type basicWeightedLines struct {
-	graph.WeightedLines
-}
-
-func TestWeightedLinesOf(t *testing.T) {
 	for _, test := range weightedLinesOfTests {
 		got := graph.WeightedLinesOf(test.lines)
 		if !reflect.DeepEqual(got, test.want) {

stat/samplemv/sample_test.go

@@ -163,11 +163,12 @@ func TestMetropolisHastings(t *testing.T) {
 	compareNormal(t, target, batch, nil, 5e-1, 5e-1)
 }
 
-// randomNormal constructs a random Normal distribution.
+// randomNormal constructs a random Normal distribution using the provided
+// random source.
 func randomNormal(dim int, src *rand.Rand) (*distmv.Normal, bool) {
 	data := make([]float64, dim*dim)
 	for i := range data {
-		data[i] = rand.Float64()
+		data[i] = src.Float64()
 	}
 	a := mat.NewDense(dim, dim, data)
 	var sigma mat.SymDense
@@ -180,6 +181,8 @@ func randomNormal(dim int, src *rand.Rand) (*distmv.Normal, bool) {
 }
 
 func compareNormal(t *testing.T, want *distmv.Normal, batch *mat.Dense, weights []float64, meanTol, covTol float64) {
+	t.Helper()
+
 	dim := want.Dim()
 	mu := want.Mean(nil)
 	var sigma mat.SymDense
@@ -224,10 +227,11 @@ func TestMetropolisHastingser(t *testing.T) {
 		{3, 103, 11, 51},
 		{3, 103, 51, 11},
 	} {
+		src := rand.New(rand.NewSource(1))
 		dim := test.dim
 
 		initial := make([]float64, dim)
-		target, ok := randomNormal(dim, nil)
+		target, ok := randomNormal(dim, src)
 		if !ok {
 			t.Fatal("bad test, sigma not pos def")
 		}
@@ -239,7 +243,7 @@ func TestMetropolisHastingser(t *testing.T) {
 
 		// Test the Metropolis Hastingser by generating all the samples, then generating
 		// the same samples with a burnin and rate.
-		src := rand.New(rand.NewSource(1))
+		src = rand.New(rand.NewSource(1))
 		proposal, ok := NewProposalNormal(sigmaImp, src)
 		if !ok {
 			t.Fatal("bad test, sigma not pos def")

unit/unit_test.go

@@ -185,20 +185,19 @@ func TestDimensionEquality(t *testing.T) {
 	}
 }
 
-var operationTests = []struct {
+func TestOperations(t *testing.T) {
+	operationTests := []struct {
 		recvOp func(Uniter) *Unit
 		param  Uniter
 		want   Uniter
-}{
+	}{
 		{Dimless(1).Unit().Add, Dimless(2), Dimless(3)},
 		{Dimless(1).Unit().Mul, Dimless(2), Dimless(2)},
 		{Dimless(1).Unit().Mul, Length(2), Length(2)},
 		{Length(1).Unit().Mul, Dimless(2), Length(2)},
 		{Dimless(1).Unit().Div, Length(2), New(0.5, Dimensions{LengthDim: -1})},
 		{Length(1).Unit().Div, Dimless(2), Length(0.5)},
-}
+	}
-
-func TestOperations(t *testing.T) {
 	t.Parallel()
 	for i, test := range operationTests {
 		var got Uniter