support multi-module (#4)

* add multimodule
* re-package modules

server/internal/generator/plotter/plotter_test.go

@@ -0,0 +1,86 @@
+package plotter_test
+
+import (
+	"testing"
+
+	"github.com/iliadenisov/galaxy/server/internal/generator/plotter"
+)
+
+func TestNewPlotter(t *testing.T) {
+	_, err := plotter.NewPlotter(10, 10, 0)
+	if err == nil {
+		t.Error("expect: error when factor=0")
+	}
+	_, err = plotter.NewPlotter(10, 10, -0.01)
+	if err == nil {
+		t.Error("expect: error when factor<0")
+	}
+	_, err = plotter.NewPlotter(10, 10, 1.001)
+	if err == nil {
+		t.Error("expect: error when factor>1")
+	}
+	_, err = plotter.NewPlotter(10, 10, 1)
+	if err != nil {
+		t.Error("expect: no error when factor=1")
+	}
+}
+
+func TestAsPlotterSize(t *testing.T) {
+	for _, tc := range []struct {
+		w, h   uint32
+		f      float64
+		ew, eh uint32
+	}{
+		{10, 10, 0, 10, 10},
+		{10, 10, -1, 10, 10},
+		{10, 10, 1.1, 10, 10},
+		{10, 20, 0.5, 20, 40},
+		{30, 60, 0.3, 100, 200},
+		{10, 20, 0.25, 40, 80},
+	} {
+		w, h := plotter.AsPlotterSize(tc.w, tc.h, tc.f)
+		if tc.ew != w || tc.eh != h {
+			t.Errorf("expect: w=%d h=%d, got: w=%d h=%d", tc.ew, tc.eh, w, h)
+		}
+	}
+}
+
+func TestRandomFreePoint(t *testing.T) {
+	var factor float64 = 0.25
+	var w, h uint32 = 20, 20
+	bm := plotter.NewBitmap(w, h, factor)
+	p, err := plotter.NewBitmapPlotter(bm, factor) // 80x80
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	x, y, err := p.RandomFreePoint(3)
+	if err != nil {
+		t.Errorf("expect: no error getting random point, got: %s", err)
+	}
+	if x > float64(w) || y > float64(w) {
+		t.Errorf("expect: point coordinates within map size %dx%d, got: x=%f y=%f", w, h, x, y)
+	}
+
+	_, _, err = p.RandomFreePoint(0)
+	if err != nil {
+		t.Errorf("expect: no error when radius is zero, got: %s", err)
+	}
+
+	_, _, err = p.RandomFreePoint(float64(w + h)) // guaranteed to mark whole area dead zone
+	if err != nil {
+		t.Errorf("expect: no error getting random point, got: %s", err)
+	}
+
+	_, _, err = p.RandomFreePoint(1)
+	if err == nil {
+		t.Error("expect: error when no free space left, got: none")
+	}
+
+	p.Clear()
+
+	_, _, err = p.RandomFreePoint(10)
+	if err != nil {
+		t.Errorf("expect: no error getting random point after clearing, got: %s", err)
+	}
+}