7329: Add generic tests for empty block handling.

diff --git a/services/keepstore/volume_generic_test.go b/services/keepstore/volume_generic_test.go
index 193d9d2c2cadfd0d2a583c404562a5be65d9754e..c08c3f5f0007ac483486cb01d1e6a4bd68253d42 100644 (file)
--- a/services/keepstore/volume_generic_test.go
+++ b/services/keepstore/volume_generic_test.go
@@ -22,12 +22,21 @@ func DoGenericVolumeTests(t *testing.T, factory TestableVolumeFactory) {
        testGet(t, factory)
        testGetNoSuchBlock(t, factory)
 
-       testCompareSameContent(t, factory)
-       testCompareWithDifferentContent(t, factory)
-       testCompareWithBadData(t, factory)
-
-       testPutBlockWithSameContent(t, factory)
-       testPutBlockWithDifferentContent(t, factory)
+       testCompareSameContent(t, factory, TestHash, TestBlock)
+       testCompareSameContent(t, factory, EmptyHash, EmptyBlock)
+       testCompareWithCollision(t, factory, TestHash, TestBlock, []byte("baddata"))
+       testCompareWithCollision(t, factory, TestHash, TestBlock, EmptyBlock)
+       testCompareWithCollision(t, factory, EmptyHash, EmptyBlock, TestBlock)
+       testCompareWithCorruptStoredData(t, factory, TestHash, TestBlock, []byte("baddata"))
+       testCompareWithCorruptStoredData(t, factory, TestHash, TestBlock, EmptyBlock)
+       testCompareWithCorruptStoredData(t, factory, EmptyHash, EmptyBlock, []byte("baddata"))
+
+       testPutBlockWithSameContent(t, factory, TestHash, TestBlock)
+       testPutBlockWithSameContent(t, factory, EmptyHash, EmptyBlock)
+       testPutBlockWithDifferentContent(t, factory, TestHash, TestBlock, TestBlock2)
+       testPutBlockWithDifferentContent(t, factory, TestHash, EmptyBlock, TestBlock)
+       testPutBlockWithDifferentContent(t, factory, TestHash, TestBlock, EmptyBlock)
+       testPutBlockWithDifferentContent(t, factory, EmptyHash, EmptyBlock, TestBlock)
        testPutMultipleBlocks(t, factory)
 
        testPutAndTouch(t, factory)
@@ -84,54 +93,56 @@ func testGetNoSuchBlock(t *testing.T, factory TestableVolumeFactory) {
 
 // Put a test block and compare the locator with same content
 // Test should pass for both writable and read-only volumes
-func testCompareSameContent(t *testing.T, factory TestableVolumeFactory) {
+func testCompareSameContent(t *testing.T, factory TestableVolumeFactory, testHash string, testData []byte) {
        v := factory(t)
        defer v.Teardown()
 
-       v.PutRaw(TestHash, TestBlock)
+       v.PutRaw(testHash, testData)
 
        // Compare the block locator with same content
-       err := v.Compare(TestHash, TestBlock)
+       err := v.Compare(testHash, testData)
        if err != nil {
                t.Errorf("Got err %q, expected nil", err)
        }
 }
 
-// Put a test block and compare the locator with a different content
-// Expect error due to collision
+// Test behavior of Compare() when stored data matches expected
+// checksum but differs from new data we need to store. Requires
+// testHash = md5(testDataA).
+//
 // Test should pass for both writable and read-only volumes
-func testCompareWithDifferentContent(t *testing.T, factory TestableVolumeFactory) {
+func testCompareWithCollision(t *testing.T, factory TestableVolumeFactory, testHash string, testDataA, testDataB []byte) {
        v := factory(t)
        defer v.Teardown()
 
-       v.PutRaw(TestHash, TestBlock)
+       v.PutRaw(testHash, testDataA)
 
        // Compare the block locator with different content; collision
-       err := v.Compare(TestHash, []byte("baddata"))
+       err := v.Compare(TestHash, testDataB)
        if err == nil {
-               t.Errorf("Expected error due to collision")
+               t.Errorf("Got err nil, expected error due to collision")
        }
 }
 
-// Put a test block with bad data (hash does not match, but Put does not verify)
-// Compare the locator with good data whose hash matches with locator
-// Expect error due to corruption.
+// Test behavior of Compare() when stored data has become
+// corrupted. Requires testHash = md5(testDataA) != md5(testDataB).
+//
 // Test should pass for both writable and read-only volumes
-func testCompareWithBadData(t *testing.T, factory TestableVolumeFactory) {
+func testCompareWithCorruptStoredData(t *testing.T, factory TestableVolumeFactory, testHash string, testDataA, testDataB []byte) {
        v := factory(t)
        defer v.Teardown()
 
-       v.PutRaw(TestHash, []byte("baddata"))
+       v.PutRaw(TestHash, testDataB)
 
-       err := v.Compare(TestHash, TestBlock)
-       if err == nil {
-               t.Errorf("Expected error due to corruption")
+       err := v.Compare(testHash, testDataA)
+       if err == nil || err == CollisionError {
+               t.Errorf("Got err %+v, expected non-collision error", err)
        }
 }
 
 // Put a block and put again with same content
 // Test is intended for only writable volumes
-func testPutBlockWithSameContent(t *testing.T, factory TestableVolumeFactory) {
+func testPutBlockWithSameContent(t *testing.T, factory TestableVolumeFactory, testHash string, testData []byte) {
        v := factory(t)
        defer v.Teardown()
 
@@ -139,12 +150,12 @@ func testPutBlockWithSameContent(t *testing.T, factory TestableVolumeFactory) {
                return
        }
 
-       err := v.Put(TestHash, TestBlock)
+       err := v.Put(testHash, testData)
        if err != nil {
                t.Errorf("Got err putting block %q: %q, expected nil", TestBlock, err)
        }
 
-       err = v.Put(TestHash, TestBlock)
+       err = v.Put(testHash, testData)
        if err != nil {
                t.Errorf("Got err putting block second time %q: %q, expected nil", TestBlock, err)
        }
@@ -152,7 +163,7 @@ func testPutBlockWithSameContent(t *testing.T, factory TestableVolumeFactory) {
 
 // Put a block and put again with different content
 // Test is intended for only writable volumes
-func testPutBlockWithDifferentContent(t *testing.T, factory TestableVolumeFactory) {
+func testPutBlockWithDifferentContent(t *testing.T, factory TestableVolumeFactory, testHash string, testDataA, testDataB []byte) {
        v := factory(t)
        defer v.Teardown()
 
@@ -160,25 +171,25 @@ func testPutBlockWithDifferentContent(t *testing.T, factory TestableVolumeFactor
                return
        }
 
-       err := v.Put(TestHash, TestBlock)
+       err := v.Put(testHash, testDataA)
        if err != nil {
-               t.Errorf("Got err putting block %q: %q, expected nil", TestBlock, err)
+               t.Errorf("Got err putting block %q: %q, expected nil", testDataA, err)
        }
 
-       putErr := v.Put(TestHash, TestBlock2)
-       buf, getErr := v.Get(TestHash)
+       putErr := v.Put(testHash, testDataB)
+       buf, getErr := v.Get(testHash)
        if putErr == nil {
                // Put must not return a nil error unless it has
                // overwritten the existing data.
-               if bytes.Compare(buf, TestBlock2) != 0 {
-                       t.Errorf("Put succeeded but Get returned %+v, expected %+v", buf, TestBlock2)
+               if bytes.Compare(buf, testDataB) != 0 {
+                       t.Errorf("Put succeeded but Get returned %+v, expected %+v", buf, testDataB)
                }
        } else {
                // It is permissible for Put to fail, but it must
                // leave us with either the original data, the new
                // data, or nothing at all.
-               if getErr == nil && bytes.Compare(buf, TestBlock) != 0 && bytes.Compare(buf, TestBlock2) != 0 {
-                       t.Errorf("Put failed but Get returned %+v, which is neither %+v nor %+v", buf, TestBlock, TestBlock2)
+               if getErr == nil && bytes.Compare(buf, testDataA) != 0 && bytes.Compare(buf, testDataB) != 0 {
+                       t.Errorf("Put failed but Get returned %+v, which is neither %+v nor %+v", buf, testDataA, testDataB)
                }
        }
        if getErr == nil {