Set up testing framework and utilities

docs/IMPLEMENTATION.md

@@ -3,10 +3,10 @@
 ## Phase 1: Proof of Work Package Implementation
 **Goal**: Create standalone, testable PoW package with HMAC-signed stateless challenges
 
-- [ ] **Project Setup**
+- [X] **Project Setup**
   - [X] Initialize Go module and basic project structure
   - [X] Create PoW challenge structure and types
-  - [ ] Set up testing framework and utilities
+  - [X] Set up testing framework and utilities
 
 - [ ] **Challenge Generation & HMAC Security**
   - [ ] Implement HMAC-signed challenge generation (stateless)

go.mod

@@ -1,3 +1,5 @@
 module word-of-wisdom
 
 go 1.24.3
+
+require github.com/stretchr/testify v1.10.0 // indirect

go.sum

@@ -0,0 +1,2 @@
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=

internal/pow/test_utils.go

@@ -0,0 +1,63 @@
+package pow
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"time"
+)
+
+// TestConfig returns a configuration suitable for testing
+func TestConfig() *Config {
+	secret := make([]byte, 32)
+	rand.Read(secret)
+
+	config, err := NewConfig(
+		WithHMACSecret(secret),
+		WithDefaultDifficulty(4),
+		WithRandomBytes(6),
+	)
+	if err != nil {
+		panic("Failed to create test config: " + err.Error())
+	}
+	return config
+}
+
+// TestChallenge returns a valid challenge for testing
+func TestChallenge() *Challenge {
+	return &Challenge{
+		Timestamp:  time.Now().Unix(),
+		Difficulty: 4,
+		Resource:   "quotes",
+		Random:     []byte{0xa1, 0xb2, 0xc3, 0xd4, 0xe5, 0xf6},
+		HMAC:       nil, // To be filled by generator
+	}
+}
+
+// TestSolution returns a valid solution for testing
+func TestSolution() *Solution {
+	return &Solution{
+		Challenge: *TestChallenge(),
+		Nonce:     42,
+	}
+}
+
+// RandomHex generates a random hex string of given length
+func RandomHex(length int) string {
+	bytes := make([]byte, length/2)
+	rand.Read(bytes)
+	return hex.EncodeToString(bytes)
+}
+
+// ExpiredChallenge returns a challenge that has expired
+func ExpiredChallenge() *Challenge {
+	challenge := TestChallenge()
+	challenge.Timestamp = time.Now().Add(-10 * time.Minute).Unix()
+	return challenge
+}
+
+// FutureChallenge returns a challenge with future timestamp
+func FutureChallenge() *Challenge {
+	challenge := TestChallenge()
+	challenge.Timestamp = time.Now().Add(10 * time.Minute).Unix()
+	return challenge
+}