feat(tools/seqstat): add a tool to report stats about a sequence

For example:
```
% echo 1 20 12 32 19 2 | ./seqstat -S
▁▅▃█▅▁
min:   1.000000
max:   32.000000
avg:   14.333333
p50:   19.000000
p90:   32.000000
p99:   32.000000
p999:  32.000000
ordered sequence: [1 2 12 19 20 32]
```

Change-Id: I9303bd7d0e964948143e77c868de8777cd7a9951
Reviewed-on: https://cl.fcuny.net/c/world/+/454
Tested-by: CI
Reviewed-by: Franck Cuny <franck@fcuny.net>

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/seqstat/sequence_test.go b/tools/seqstat/sequence_test.go
new file mode 100644
index 0000000..1299086
--- /dev/null
+++ b/tools/seqstat/sequence_test.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestHistogram(t *testing.T) {
+	cases := []struct {
+		in        []float64
+		histogram []rune
+	}{
+		{[]float64{1, 2}, []rune{'▁', '█'}},
+		{[]float64{1, 10, 4}, []rune{'▁', '█', '▃'}},
+		{[]float64{1, 5, 22, 13, 53}, []rune{'▁', '▁', '▃', '▂', '█'}},
+	}
+
+	for _, c := range cases {
+		seq := newSequence(c.in)
+		if string(seq.histogram()) != string(c.histogram) {
+			t.Errorf("Not matching: got %q, want %q", string(seq.histogram()), string(c.histogram))
+		}
+	}
+}
+
+func TestStats(t *testing.T) {
+	cases := []struct {
+		in   []float64
+		min  float64
+		max  float64
+		p999 float64
+	}{
+		{[]float64{1, 10, 52, 12}, 1, 52, 52},
+	}
+
+	for _, c := range cases {
+		seq := newSequence(c.in)
+		if seq.min != c.min {
+			t.Errorf("Not matching: got min %f want %f", seq.min, c.min)
+		}
+		if seq.max != c.max {
+			if seq.max != c.max {
+				t.Errorf("Not matching: got max %f want %f", seq.max, c.max)
+			}
+			if seq.p999() != c.p999 {
+				t.Errorf("Not matching: got p999 %f want %f", seq.p999(), c.p999)
+			}
+		}
+	}
+}