test(mining): add CheckNonce and OnNewTemplate coverage

Brings mining/ package coverage from 78% to 86.6%.

Co-Authored-By: Charon <charon@lethean.io>

mining/hash_test.go

@@ -99,3 +99,53 @@ func TestHeaderMiningHash_Good_NonceIgnored(t *testing.T) {
 			block1.Nonce, h1, block2.Nonce, h2)
 	}
 }
+
+func TestCheckNonce_Good_LowDifficulty(t *testing.T) {
+	// Build a genesis block and compute its header hash.
+	rawTx := testnetGenesisRawTx()
+	dec := wire.NewDecoder(bytes.NewReader(rawTx))
+	minerTx := wire.DecodeTransaction(dec)
+	if dec.Err() != nil {
+		t.Fatalf("decode genesis tx: %v", dec.Err())
+	}
+
+	block := types.Block{
+		BlockHeader: testnetGenesisHeader(),
+		MinerTx:     minerTx,
+	}
+	headerHash := HeaderMiningHash(&block)
+
+	// With difficulty=1, any nonce should produce a valid solution.
+	ok, err := CheckNonce(headerHash, 0, 1)
+	if err != nil {
+		t.Fatalf("CheckNonce: %v", err)
+	}
+	if !ok {
+		t.Error("CheckNonce should pass with difficulty=1")
+	}
+}
+
+func TestCheckNonce_Good_HighDifficulty(t *testing.T) {
+	// With extremely high difficulty, nonce=0 should NOT produce a valid solution.
+	rawTx := testnetGenesisRawTx()
+	dec := wire.NewDecoder(bytes.NewReader(rawTx))
+	minerTx := wire.DecodeTransaction(dec)
+	if dec.Err() != nil {
+		t.Fatalf("decode genesis tx: %v", dec.Err())
+	}
+
+	block := types.Block{
+		BlockHeader: testnetGenesisHeader(),
+		MinerTx:     minerTx,
+	}
+	headerHash := HeaderMiningHash(&block)
+
+	// With difficulty = max uint64, virtually no hash passes.
+	ok, err := CheckNonce(headerHash, 0, ^uint64(0))
+	if err != nil {
+		t.Fatalf("CheckNonce: %v", err)
+	}
+	if ok {
+		t.Error("CheckNonce should fail with max difficulty")
+	}
+}

mining/miner_test.go

@@ -290,6 +290,38 @@ func (f *failingSubmitter) SubmitBlock(hexBlob string) error {
 	return fmt.Errorf("connection refused")
 }
 
+func TestMiner_Start_Good_OnNewTemplate(t *testing.T) {
+	var tmplHeight uint64
+	var tmplDiff uint64
+
+	mock := &mockProvider{
+		templates: []*rpc.BlockTemplateResponse{
+			{Difficulty: "42", Height: 300, BlockTemplateBlob: hex.EncodeToString(minimalBlockBlob(t)), Status: "OK"},
+		},
+		infos: []*rpc.DaemonInfo{{Height: 300}},
+	}
+
+	cfg := Config{
+		DaemonURL:    "http://localhost:46941",
+		WalletAddr:   "iTHNtestaddr",
+		PollInterval: 100 * time.Millisecond,
+		Provider:     mock,
+		OnNewTemplate: func(height uint64, difficulty uint64) {
+			tmplHeight = height
+			tmplDiff = difficulty
+		},
+	}
+	m := NewMiner(cfg)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
+	defer cancel()
+
+	_ = m.Start(ctx)
+
+	assert.Equal(t, uint64(300), tmplHeight)
+	assert.Equal(t, uint64(42), tmplDiff)
+}
+
 func TestMiner_Start_Bad_SubmitFails(t *testing.T) {
 	mock := &failingSubmitter{
 		mockProvider: mockProvider{