go(stats/table): let the printing func just print

...and handle constructing the actual table in a separate func.
also, add more tests.

stats/table.go

@@ -34,12 +34,15 @@ func PrintStatisticTable(algoStats [][]Stats) {
 	fmt.Fprintln(os.Stderr, "printing statistic table data (min, max, mean, median, stddev)")
 
 	for _, singleFunc := range algoStats {
-		statsSingleFunc(singleFunc)
+		fmt.Fprintln(os.Stderr, statsSingleFunc(singleFunc))
 	}
 }
 
-// statsSingleFunc computes statistics out of results of  a single bench func.
-func statsSingleFunc(singleFuncStats []Stats) {
+// statsSingleFunc computes statistics out of results of a single bench func
+// and returns the statistic table as a []interface{} because it contains
+// multiple table headers and rows. perhaps a table struct could be returned in
+// the future.
+func statsSingleFunc(singleFuncStats []Stats) []interface{} {
 	var (
 		// hdr is the table header as determined based on the data being dealt with.
 		hdr statsHdr
@@ -47,6 +50,10 @@ func statsSingleFunc(singleFuncStats []Stats) {
 		row statsRow
 	)
 
+	// out contains the constructed table and is returned at the end of
+	// this func.
+	out := make([]interface{}, 0)
+
 	for _, s := range singleFuncStats {
 		for _, dim := range s.BenchFuncStats {
 			hdr = makeTableHdr(
@@ -56,7 +63,7 @@ func statsSingleFunc(singleFuncStats []Stats) {
 				s.Generations,
 				s.Iterations,
 			)
-			fmt.Fprintln(os.Stderr, hdr)
+			out = append(out, "\n", hdr, "\n")
 
 			// collect the best.
 			var best []float64
@@ -73,9 +80,13 @@ func statsSingleFunc(singleFuncStats []Stats) {
 			row.Median = stat.Mean(best, nil)
 			row.StdDev = stat.StdDev(best, nil)
 
-			fmt.Fprintln(os.Stderr, row)
+			out = append(out, row)
 		}
 	}
+
+	out = append(out, "\n")
+
+	return out
 }
 
 // makeTableHdr fills the table header with passed information.

stats/table_test.go

@@ -27,3 +27,45 @@ func TestNewStatsHdr(t *testing.T) {
 		t.Error("could not create hdr")
 	}
 }
+
+func TestStatsSingleFunc(t *testing.T) {
+	testHdr := makeTableHdr("Aladeen Search", "De Jong 5th", 5, 3, 4)
+	benchFuncStats := []FuncStats{
+		{
+			BenchName: "De Jong 5th",
+			Solution: []BenchRound{
+				{Iteration: 0, Results: []float64{2803.7015205977887, 2296.736381649773, 1763.9319525203364}},
+				{Iteration: 1, Results: []float64{2169.7378893600176, 2169.7378893600176, 2169.7378893600176}},
+				{Iteration: 2, Results: []float64{1909.6488355929007, 1336.3261400058473, 1336.3261400058473}},
+				{Iteration: 3, Results: []float64{2227.0782796718786, 2227.0782796718786, 1681.0667739991388}},
+			},
+		},
+	}
+	testStats := []Stats{
+		{
+			Algo:           "Aladeen Search",
+			Dimens:         5,
+			BenchFuncStats: benchFuncStats,
+			Iterations:     4,
+			Generations:    3,
+		},
+	}
+	want := []interface{}{
+		"\n",
+		testHdr,
+		"\n",
+		statsRow{1336.3261400058473, 2169.7378893600176, 1737.765688971335, 1737.765688971335, 342.37072192259393},
+		"\n",
+	}
+	got := statsSingleFunc(testStats)
+
+	if len(want) != len(got) {
+		t.Errorf("outputs are of different sizes, want: %d, got: %d", len(want), len(got))
+	}
+
+	for i := range want {
+		if want[i] != got[i] {
+			t.Errorf("outputs don't match, want: %v, got: %v", want, got)
+		}
+	}
+}