Add tests for new Block API functions.

This commit adds both positive and negative tests for the new Tx and
Transactions Block API functions.

This is part of the ongoing transaction hash optimization effort noted in
conformal/btcd#25.

block_test.go

@@ -61,7 +61,7 @@ func TestBlock(t *testing.T) {
 		"e9a66845e05d5abc0ad04ec80f774a7e585c6e8db975962d069a522137b80c1d",
 	}
 
-	// Request sha for all transactions one at a time.
+	// Request sha for all transactions one at a time via TxSha.
 	for i, txSha := range wantTxShas {
 		wantSha, err := btcwire.NewShaHashFromStr(txSha)
 		if err != nil {
@@ -75,6 +75,7 @@ func TestBlock(t *testing.T) {
 				t.Errorf("TxSha: %v", err)
 				continue
 			}
+
 			if !sha.IsEqual(wantSha) {
 				t.Errorf("TxSha #%d mismatched sha - got %v, "+
 					"want %v", j, sha, wantSha)
@@ -86,6 +87,33 @@ func TestBlock(t *testing.T) {
 	// Create a new block to nuke all cached data.
 	b = btcutil.NewBlock(&Block100000)
 
+	// Request sha for all transactions one at a time via Tx.
+	for i, txSha := range wantTxShas {
+		wantSha, err := btcwire.NewShaHashFromStr(txSha)
+		if err != nil {
+			t.Errorf("NewShaHashFromStr: %v", err)
+		}
+
+		// Request the sha multiple times to test generation and caching.
+		for j := 0; j < 2; j++ {
+			tx, err := b.Tx(i)
+			if err != nil {
+				t.Errorf("Tx #%d: %v", i, err)
+				continue
+			}
+
+			sha := tx.Sha()
+			if !sha.IsEqual(wantSha) {
+				t.Errorf("Sha #%d mismatched sha - got %v, "+
+					"want %v", j, sha, wantSha)
+				continue
+			}
+		}
+	}
+
+	// Create a new block to nuke all cached data.
+	b = btcutil.NewBlock(&Block100000)
+
 	// Request slice of all transaction shas multiple times to test
 	// generation and caching.
 	for i := 0; i < 2; i++ {
@@ -120,6 +148,38 @@ func TestBlock(t *testing.T) {
 		}
 	}
 
+	// Create a new block to nuke all cached data.
+	b = btcutil.NewBlock(&Block100000)
+
+	// Request slice of all transactions multiple times to test generation
+	// and caching.
+	for i := 0; i < 2; i++ {
+		transactions := b.Transactions()
+
+		// Ensure we get the expected number of transactions.
+		if len(transactions) != len(wantTxShas) {
+			t.Errorf("Transactions #%d mismatched number of "+
+				"transactions - got %d, want %d", i,
+				len(transactions), len(wantTxShas))
+			continue
+		}
+
+		// Ensure all of the shas match.
+		for j, tx := range transactions {
+			wantSha, err := btcwire.NewShaHashFromStr(wantTxShas[j])
+			if err != nil {
+				t.Errorf("NewShaHashFromStr: %v", err)
+			}
+
+			sha := tx.Sha()
+			if !sha.IsEqual(wantSha) {
+				t.Errorf("Transactions #%d mismatched shas - "+
+					"got %v, want %v", j, sha, wantSha)
+				continue
+			}
+		}
+	}
+
 	// Serialize the test block.
 	var block100000Buf bytes.Buffer
 	err = Block100000.Serialize(&block100000Buf)
@@ -277,6 +337,18 @@ func TestBlockErrors(t *testing.T) {
 			"want: <%T>", err, err, btcutil.OutOfRangeError(""))
 	}
 
+	// Ensure Tx returns expected error on invalid indices.
+	_, err = b.Tx(-1)
+	if _, ok := err.(btcutil.OutOfRangeError); !ok {
+		t.Errorf("Tx: wrong error - got: %v <%T>, "+
+			"want: <%T>", err, err, btcutil.OutOfRangeError(""))
+	}
+	_, err = b.Tx(len(Block100000.Transactions) + 1)
+	if _, ok := err.(btcutil.OutOfRangeError); !ok {
+		t.Errorf("Tx: wrong error - got: %v <%T>, "+
+			"want: <%T>", err, err, btcutil.OutOfRangeError(""))
+	}
+
 	// Ensure TxLoc returns expected error with short byte buffer.
 	// This makes use of the test package only function, SetBlockBytes, to
 	// inject a short byte buffer.