Cover the loss window, rate window, error taxonomy and formatters with tests

render_test.go

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"testing"
+	"time"
+)
+
+func TestScaleSI(t *testing.T) {
+	for _, c := range []struct {
+		in   float64
+		want string
+	}{
+		{0, "0.00"},
+		{999, "999.00"},
+		{1000, "1.00 k"},
+		{1234567, "1.23 M"},
+		{1e12, "1.00 T"},
+		{1e15, "1.00 P"},
+	} {
+		if got := scaleSI(c.in); got != c.want {
+			t.Errorf("scaleSI(%v) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}
+
+// Below a thousand a count is the count, since two decimals on a quantity that
+// cannot have them read as precision that is not there.
+func TestScaleCount(t *testing.T) {
+	for _, c := range []struct {
+		in   uint64
+		want string
+	}{
+		{0, "0"},
+		{999, "999"},
+		{1000, "1.00 k"},
+	} {
+		if got := scaleCount(c.in); got != c.want {
+			t.Errorf("scaleCount(%d) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}
+
+func TestScaleTime(t *testing.T) {
+	for _, c := range []struct {
+		in   time.Duration
+		want string
+	}{
+		{1500 * time.Millisecond, "1.50 s"},
+		{90 * time.Second, "1.50 m"},
+		{90 * time.Minute, "1.50 h"},
+		{36 * time.Hour, "1.50 d"},
+	} {
+		if got := scaleTime(c.in); got != c.want {
+			t.Errorf("scaleTime(%v) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}
+
+func TestCommas(t *testing.T) {
+	for _, c := range []struct {
+		in   uint64
+		want string
+	}{
+		{0, "0"},
+		{999, "999"},
+		{1000, "1,000"},
+		{1234567, "1,234,567"},
+	} {
+		if got := commas(c.in); got != c.want {
+			t.Errorf("commas(%d) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}
+
+// The table only lines up if colour codes are not counted as width.
+func TestPadIgnoresColour(t *testing.T) {
+	if got := visWidth(paint("ok", cGreen)); got != 2 {
+		t.Errorf("visWidth = %d, want 2", got)
+	}
+	if got := visWidth(pad(paint("ok", cGreen), 6, true)); got != 6 {
+		t.Errorf("padded width = %d, want 6", got)
+	}
+}
+
+// The break between the two halves of the row has to be the same width on the
+// header, the rule and every value line, or the columns drift apart.
+func TestStreamTableBreakAligns(t *testing.T) {
+	tbl := &streamTable{cols: intervalCols}
+	lines := tbl.headerLines()
+	row := tbl.emit(make([]string, len(intervalCols)))
+	widths := map[string]int{}
+	for _, l := range append(lines, row...) {
+		widths[l] = visWidth(l)
+	}
+	var first int
+	for _, w := range widths {
+		if first == 0 {
+			first = w
+			continue
+		}
+		if w != first {
+			t.Fatalf("header and value lines disagree on width: %v", widths)
+		}
+	}
+	if first != tbl.width() {
+		t.Errorf("lines are %d wide, width() reports %d", first, tbl.width())
+	}
+}