From b257a60b2d29eeadc0e262026fa473ee16d4f014 Mon Sep 17 00:00:00 2001
From: "Sascha L. Teichmann" <sascha.teichmann@intevation.de>
Date: Wed, 11 May 2016 11:39:50 +0200
Subject: [PATCH] Improved tests of base tile hash. They fail. TODO: Fix bugs
 in base tile hash.

---
 common/basetilehash_test.go | 118 ++++++++++++++++++++++++++++++++----
 1 file changed, 105 insertions(+), 13 deletions(-)

diff --git a/common/basetilehash_test.go b/common/basetilehash_test.go
index 7aa89c6..6e7fd7e 100644
--- a/common/basetilehash_test.go
+++ b/common/basetilehash_test.go
@@ -4,24 +4,116 @@
 
 package common
 
-import "testing"
+import (
+	"math/rand"
+	"testing"
+)
 
-func TestBaseTileHash(t *testing.T) {
+func randomBaseTileHash(updates int) *BaseTileHash {
 	bth := NewBaseTileHash(256)
 	h1 := []byte{1}
 	h2 := []byte{2}
-	for i := 0; i < 600; i++ {
-		x := i % 200
-		for j := 0; j < 600; j++ {
-			y := j % 200
-			var h []byte
-			if j%2 == 0 {
-				h = h1
-			} else {
-				h = h2
+	for i := 0; i < updates; i++ {
+		x, y := rand.Intn(100), rand.Intn(100)
+		var h []byte
+		if i%2 == 0 {
+			h = h1
+		} else {
+			h = h2
+		}
+		bth.Update(x, y, h)
+	}
+	return bth
+}
+
+func TestBaseTileHash(t *testing.T) {
+	for _, updates := range []int{10, 100, 1000, 10000} {
+		bth := randomBaseTileHash(updates)
+		entries := map[*btHashEntry]bool{}
+
+		for cur := bth.root.next; cur != &bth.root; cur = cur.next {
+			if entries[cur] {
+				t.Errorf("hash element found more than once: %d", updates)
 			}
-			_ = bth.Update(x, y, h)
+			entries[cur] = true
+		}
+		if len(entries) != len(bth.hashes) {
+			t.Errorf("List has differnt length than hashes: %d : %d",
+				len(entries), len(bth.hashes))
+		}
+		for k, v := range bth.hashes {
+			if !entries[v] {
+				t.Errorf("Hash contains pointer to element not being in list: %d",
+					updates)
+			}
+			if k != v.btKey {
+				t.Error("Key in entry does not match hash key: %d", updates)
+			}
+			delete(entries, v)
+		}
+
+		if len(entries) > 0 {
+			t.Error("There a are more entries than indexed by hash")
 		}
 	}
-	t.Logf("size: %d\n", len(bth.hashes))
+}
+
+func TestBaseTileHashOverwrite(t *testing.T) {
+	bth := NewBaseTileHash(256)
+	h1 := []byte{1}
+	h2 := []byte{2}
+
+	if updated := bth.Update(0, 0, h1); !updated {
+		t.Error("First insert does not trigger update")
+	}
+
+	if updated := bth.Update(0, 0, h2); !updated {
+		t.Error("Second insert does not trigger update")
+	}
+
+	if updated := bth.Update(0, 0, h2); updated {
+		t.Error("Third insert does trigger update")
+	}
+}
+
+func TestBaseTileHashSeparate(t *testing.T) {
+	bth := NewBaseTileHash(256)
+	h1 := []byte{1}
+
+	if updated := bth.Update(0, 0, h1); !updated {
+		t.Error("First insert does not trigger update")
+	}
+
+	if updated := bth.Update(0, 1, h1); !updated {
+		t.Error("Second insert does not trigger update")
+	}
+
+	if updated := bth.Update(1, 0, h1); !updated {
+		t.Error("Third insert does trigger update")
+	}
+
+	if len(bth.hashes) != 3 {
+		t.Errorf("Expected size to be 3. Current size: %d", len(bth.hashes))
+	}
+}
+
+func TestBaseTileHashLRU(t *testing.T) {
+	bth := NewBaseTileHash(2)
+	h1 := []byte{1}
+
+	if updated := bth.Update(0, 0, h1); !updated {
+		t.Error("First insert does not trigger update")
+	}
+
+	if updated := bth.Update(0, 1, h1); !updated {
+		t.Error("Second insert does not trigger update")
+	}
+
+	if updated := bth.Update(1, 0, h1); !updated {
+		t.Error("Third insert does trigger update")
+	}
+
+	if len(bth.hashes) != 2 {
+		t.Errorf("Expected size to be 2. Current size: %d", len(bth.hashes))
+	}
 }