Add negative test for TxLoc.

block_test.go

@@ -286,7 +286,6 @@ func TestBlockErrors(t *testing.T) {
 	if err != io.EOF {
 		t.Errorf("NewBlockFromBytes: did not get expected error - "+
 			"got %v, want %v", err, io.EOF)
-		return
 	}
 
 	// Ensure TxSha returns expected error on invalid indices.
@@ -300,6 +299,16 @@ func TestBlockErrors(t *testing.T) {
 		t.Errorf("TxSha: 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.
+	b.SetBlockBytes(shortBytes)
+	_, err = b.TxLoc()
+	if err != io.EOF {
+		t.Errorf("TxLoc: did not get expected error - "+
+			"got %v, want %v", err, io.EOF)
+	}
 }
 
 // Block100000 defines block 100,000 of the block chain.  It is used to

internal_test.go

@@ -0,0 +1,18 @@
+// Copyright (c) 2013 Conformal Systems LLC.
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+/*
+This test file is part of the btcutil package rather than than the
+btcutil_test package so it can bridge access to the internals to properly test
+cases which are either not possible or can't reliably be tested via the public
+interface. The functions are only exported while the tests are being run.
+*/
+
+package btcutil
+
+// SetBlockBytes sets the internal raw block byte buffer to the passed buffer.
+// It is used to inject errors and only available to the test package.
+func (b *Block) SetBlockBytes(buf []byte) {
+	b.rawBlock = buf
+}

test_coverage.txt

@@ -10,7 +10,7 @@ github.com/conformal/btcutil/block.go	 NewBlock			 100.00% (1/1)
 github.com/conformal/btcutil/block.go	 NewBlockFromBlockAndBytes	 100.00% (1/1)
 github.com/conformal/btcutil/block.go	 Block.Height			 100.00% (1/1)
 github.com/conformal/btcutil/block.go	 Block.SetHeight		 100.00% (1/1)
+github.com/conformal/btcutil/block.go	 Block.TxLoc			 88.89% (8/9)
 github.com/conformal/btcutil/block.go	 Block.Bytes			 88.89% (8/9)
-github.com/conformal/btcutil/block.go	 Block.TxLoc			 77.78% (7/9)
-github.com/conformal/btcutil		 -------------------------	 94.83% (55/58)
+github.com/conformal/btcutil		 -------------------------	 96.55% (56/58)