Reorganize packages, closes #79

- All packages go into either cmd or pkg directories
- Most packages renamed
- Server packages moved into pkg/server
- sanitize moved into webui, as that's the only place it's used
- filestore moved into pkg/storage/file
- Makefile updated, and PKG variable use fixed

pkg/storage/lock_test.go

@@ -0,0 +1,61 @@
+package datastore_test
+
+import (
+	"testing"
+
+	"github.com/jhillyerd/inbucket/pkg/storage"
+)
+
+func TestHashLock(t *testing.T) {
+	hl := &datastore.HashLock{}
+
+	// Invalid hashes
+	testCases := []struct {
+		name, input string
+	}{
+		{"empty", ""},
+		{"short", "a0"},
+		{"badhex", "zzzzzzzzzzzzzzzzzzzzzzz"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.input, func(t *testing.T) {
+			l := hl.Get(tc.input)
+			if l != nil {
+				t.Errorf("Expected nil lock for %s %q, got %v", tc.name, tc.input, l)
+			}
+		})
+	}
+
+	// Valid hashes
+	testStrings := []string{
+		"deadbeef",
+		"00000000",
+		"ffffffff",
+	}
+	for _, ts := range testStrings {
+		t.Run(ts, func(t *testing.T) {
+			l := hl.Get(ts)
+			if l == nil {
+				t.Errorf("Expeced non-nil lock for hex string %q", ts)
+			}
+		})
+	}
+
+	a := hl.Get("deadbeef")
+	b := hl.Get("deadbeef")
+	if a != b {
+		t.Errorf("Expected identical locks for identical hashes, got: %p != %p", a, b)
+	}
+
+	a = hl.Get("deadbeef")
+	b = hl.Get("d3adb33f")
+	if a == b {
+		t.Errorf("Expected different locks for different hashes, got: %p == %p", a, b)
+	}
+
+	a = hl.Get("deadbeef")
+	b = hl.Get("deadb33f")
+	if a != b {
+		t.Errorf("Expected identical locks for identical leading hashes, got: %p != %p", a, b)
+	}
+}