diff --git a/cmd/gochain/main.go b/cmd/gochain/main.go
index 06ab7d0..4b09a79 100644
--- a/cmd/gochain/main.go
+++ b/cmd/gochain/main.go
@@ -1 +1,22 @@
 package main
+
+import (
+	"fmt"
+	"github.com/NicholasRodrigues/go-chain/internal/blockchain"
+)
+
+func main() {
+	bc := blockchain.NewBlockchain()
+
+	bc.AddBlock("First Block after Genesis")
+	bc.AddBlock("Second Block after Genesis")
+
+	for _, block := range bc.Blocks {
+		fmt.Printf("Prev. hash: %x\n", block.PrevBlockHash)
+		fmt.Printf("Data: %s\n", block.Data)
+		fmt.Printf("Hash: %x\n", block.Hash)
+		fmt.Println()
+	}
+
+	fmt.Println("Is blockchain valid?", bc.IsValid())
+}
diff --git a/internal/blockchain/block_test.go b/internal/blockchain/block_test.go
index 681d83f..97cafd2 100644
--- a/internal/blockchain/block_test.go
+++ b/internal/blockchain/block_test.go
@@ -14,7 +14,7 @@ func TestSetHash(t *testing.T) {
 	block := &Block{
 		Timestamp:     time.Now().Unix(),
 		Data:          []byte(data),
-		prevBlockHash: prevHash,
+		PrevBlockHash: prevHash,
 		Counter:       0,
 	}
 	block.SetHash()
@@ -33,8 +33,8 @@ func TestNewBlock(t *testing.T) {
 	if block.Data == nil || !bytes.Equal(block.Data, []byte(data)) {
 		t.Errorf("expected data %s, got %s", data, string(block.Data))
 	}
-	if block.prevBlockHash == nil || !bytes.Equal(block.prevBlockHash, prevHash) {
-		t.Errorf("expected previous hash %x, got %x", prevHash, block.prevBlockHash)
+	if block.PrevBlockHash == nil || !bytes.Equal(block.PrevBlockHash, prevHash) {
+		t.Errorf("expected previous hash %x, got %x", prevHash, block.PrevBlockHash)
 	}
 	if block.Hash == nil || len(block.Hash) == 0 {
 		t.Error("expected non-nil and non-empty hash")
@@ -42,26 +42,14 @@ func TestNewBlock(t *testing.T) {
 }
 
 func TestNewGenesisBlock(t *testing.T) {
-	block := NewGenesisBlock()
-
-	if block.Data == nil || string(block.Data) != "Genesis Block" {
-		t.Errorf("expected data 'Genesis Block', got %s", string(block.Data))
-	}
-	if block.prevBlockHash == nil || len(block.prevBlockHash) != 0 {
-		t.Error("expected empty previous hash")
-	}
-	if block.Hash == nil || len(block.Hash) == 0 {
-		t.Error("expected non-nil and non-empty hash")
+	genesisBlock := NewGenesisBlock()
+	if genesisBlock == nil {
+		t.Fatalf("Expected genesis block to be created")
 	}
-}
-
-func TestNewBlockchain(t *testing.T) {
-	bc := NewBlockchain()
-
-	if len(bc.blocks) != 1 {
-		t.Errorf("expected blockchain length 1, got %d", len(bc.blocks))
+	if len(genesisBlock.Hash) == 0 {
+		t.Errorf("Expected genesis block hash to be set")
 	}
-	if string(bc.blocks[0].Data) != "Genesis Block" {
-		t.Errorf("expected genesis block data 'Genesis Block', got %s", string(bc.blocks[0].Data))
+	if !bytes.Equal(genesisBlock.PrevBlockHash, []byte{}) {
+		t.Errorf("Expected genesis block to have no previous block hash")
 	}
 }
diff --git a/internal/blockchain/blockchain_test.go b/internal/blockchain/blockchain_test.go
index 7d7aec7..1db318c 100644
--- a/internal/blockchain/blockchain_test.go
+++ b/internal/blockchain/blockchain_test.go
@@ -5,21 +5,67 @@ import (
 	"testing"
 )
 
+func TestProofOfWork_Run(t *testing.T) {
+	block := NewBlock("test data", []byte{})
+	pow := NewProofOfWork(block)
+
+	hash, nonce := pow.Run()
+	block.Hash = hash[:]
+	block.Counter = nonce
+
+	if !pow.Validate() {
+		t.Errorf("Proof of work validation failed for block with hash %x", block.Hash)
+	}
+}
+
+func TestProofOfWork_Validate(t *testing.T) {
+	block := NewBlock("test data", []byte{})
+	pow := NewProofOfWork(block)
+
+	hash, nonce := pow.Run()
+	block.Hash = hash[:]
+	block.Counter = nonce
+
+	if !pow.Validate() {
+		t.Errorf("Expected block to be valid, but validation failed")
+	}
+}
+
+func TestNewBlockchain(t *testing.T) {
+	bc := NewBlockchain()
+	if bc == nil {
+		t.Fatalf("Expected blockchain to be created")
+	}
+	if len(bc.Blocks) != 1 {
+		t.Fatalf("Expected blockchain to have one block, got %d", len(bc.Blocks))
+	}
+	if !bytes.Equal(bc.Blocks[0].Hash, NewGenesisBlock().Hash) {
+		t.Errorf("Expected genesis block hash to match")
+	}
+}
+
 func TestAddBlock(t *testing.T) {
 	bc := NewBlockchain()
-	bc.AddBlock("New Block 1")
-	bc.AddBlock("New Block 2")
+	bc.AddBlock("First Block after Genesis")
+	bc.AddBlock("Second Block after Genesis")
 
-	if len(bc.blocks) != 3 {
-		t.Errorf("expected blockchain length 3, got %d", len(bc.blocks))
+	if len(bc.Blocks) != 3 {
+		t.Fatalf("Expected blockchain to have three Blocks, got %d", len(bc.Blocks))
 	}
-	if string(bc.blocks[1].Data) != "New Block 1" {
-		t.Errorf("expected block 1 data 'New Block 1', got %s", string(bc.blocks[1].Data))
+	if !bytes.Equal(bc.Blocks[1].PrevBlockHash, bc.Blocks[0].Hash) {
+		t.Errorf("Expected first block to reference genesis block hash")
 	}
-	if string(bc.blocks[2].Data) != "New Block 2" {
-		t.Errorf("expected block 2 data 'New Block 2', got %s", string(bc.blocks[2].Data))
+	if !bytes.Equal(bc.Blocks[2].PrevBlockHash, bc.Blocks[1].Hash) {
+		t.Errorf("Expected second block to reference first block hash")
 	}
-	if !bytes.Equal(bc.blocks[2].prevBlockHash, bc.blocks[1].Hash) {
-		t.Errorf("expected block 2 previous hash to match block 1 hash")
+}
+
+func TestBlockchain_IsValid(t *testing.T) {
+	bc := NewBlockchain()
+	bc.AddBlock("First Block after Genesis")
+	bc.AddBlock("Second Block after Genesis")
+
+	if !bc.IsValid() {
+		t.Errorf("Expected blockchain to be valid")
 	}
 }
diff --git a/internal/blockchain/validations_test.go b/internal/blockchain/validations_test.go
index c13eac5..f171827 100644
--- a/internal/blockchain/validations_test.go
+++ b/internal/blockchain/validations_test.go
@@ -13,7 +13,7 @@ func TestContentValidatePredicate(t *testing.T) {
 		t.Error("expected blockchain to be valid")
 	}
 
-	bc.blocks[1].Hash = bc.blocks[0].Hash
+	bc.Blocks[1].Hash = bc.Blocks[0].Hash
 	if ContentValidatePredicate(bc) {
 		t.Error("expected blockchain to be invalid")
 	}
@@ -33,13 +33,13 @@ func TestInputContributionFunction(t *testing.T) {
 
 	InputContributionFunction(data, bc, round, input, receive)
 
-	if len(bc.blocks) != 2 {
-		t.Errorf("expected blockchain length 2, got %d", len(bc.blocks))
+	if len(bc.Blocks) != 2 {
+		t.Errorf("expected blockchain length 2, got %d", len(bc.Blocks))
 	}
 
 	concat_data := "input data" + "received data"
-	if string(bc.blocks[1].Data) != concat_data {
-		t.Errorf("expected block data %s, got %s", concat_data, string(bc.blocks[1].Data))
+	if string(bc.Blocks[1].Data) != concat_data {
+		t.Errorf("expected block data %s, got %s", concat_data, string(bc.Blocks[1].Data))
 	}
 
 	if !ContentValidatePredicate(bc) {