tests: Added GTests for base/chunk_generator.hh

Change-Id: Ic6ededfc7fed1f91a75e48a0933e61b4670e5af1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21679
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
diff --git a/src/base/SConscript b/src/base/SConscript
index 661a219..09bcf3f 100644
--- a/src/base/SConscript
+++ b/src/base/SConscript
@@ -102,6 +102,7 @@
 GTest('sat_counter.test', 'sat_counter.test.cc')
 GTest('refcnt.test','refcnt.test.cc')
 GTest('condcodes.test', 'condcodes.test.cc')
+GTest('chunk_generator.test', 'chunk_generator.test.cc')
 
 DebugFlag('Annotate', "State machine annotation debugging")
 DebugFlag('AnnotateQ', "State machine annotation queue debugging")
diff --git a/src/base/chunk_generator.test.cc b/src/base/chunk_generator.test.cc
new file mode 100644
index 0000000..5e8209d
--- /dev/null
+++ b/src/base/chunk_generator.test.cc
@@ -0,0 +1,224 @@
+/*
+ * Copyright (c) 2019 The Regents of the University of California
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Bobby R. Bruce
+ */
+
+#include <gtest/gtest.h>
+
+#include "chunk_generator.hh"
+
+
+/*
+ * A test to ensure the object is in a sane state after initialization.
+ */
+TEST(ChunkGeneratorTest, StartingConditions)
+{
+    ChunkGenerator chunk_generator(0, 1024, 8);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_EQ(8, chunk_generator.size());
+    EXPECT_EQ(0, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_FALSE(chunk_generator.last());
+}
+
+/*
+ * A simple test to check the move to the next chunk under normal conditions.
+ */
+TEST(ChunkGeneratorTest, AdvanceToNextChunk)
+{
+    ChunkGenerator chunk_generator(0, 1024, 8);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(8, chunk_generator.addr());
+    EXPECT_EQ(8, chunk_generator.size());
+    EXPECT_EQ(8, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_FALSE(chunk_generator.last());
+}
+
+/*
+ * A test to consume chunks until the last chunk.
+ */
+TEST(ChunkGeneratorTest, AdvanceToLastChunk)
+{
+    ChunkGenerator chunk_generator(0, 32, 8);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(8, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(16, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(24, chunk_generator.addr());
+    EXPECT_EQ(8, chunk_generator.size());
+    EXPECT_EQ(24, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+}
+
+/*
+ * A test to consume chunks, inclusive of the last chunk.
+ */
+TEST(ChunkGeneratorTest, AdvanceToTheEnd)
+{
+    ChunkGenerator chunk_generator(0, 32, 8);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(8, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(16, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(24, chunk_generator.addr());
+    /* The following returns false because we cannot advance to the next to
+     * the next chunk (it does not exist). However, we still process the last
+     * chunk. It is therefore not indicative of failure to change the
+     * state of the object.
+     */
+    EXPECT_FALSE(chunk_generator.next());
+    EXPECT_EQ(24, chunk_generator.addr());
+    EXPECT_EQ(0, chunk_generator.size());
+    EXPECT_EQ(24, chunk_generator.complete());
+    EXPECT_TRUE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+}
+
+/*
+ * A region does is not necessisarily divisable by the chunk size. This will
+ * will result in the final chunk being smaller than the rest.
+ */
+TEST(ChunkGeneratorTest, SmallerLastChunk)
+{
+    // There are two chunks. The last will be 6 bytes.
+    ChunkGenerator chunk_generator(0, 14, 8);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(8, chunk_generator.addr());
+    EXPECT_EQ(6, chunk_generator.size());
+    EXPECT_EQ(8, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+}
+
+/*
+ * When a chunk size is greater than the total size, the chunk size
+ * is effectively that of the region size. This test will verify this
+ * corner-case.
+ */
+TEST(ChunkGeneratorTest, ChunkSizeGreaterThanTotalSize)
+{
+    ChunkGenerator chunk_generator(0, 32, 64);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_EQ(32, chunk_generator.size());
+    EXPECT_EQ(0, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+
+    // Process the entire region.
+    EXPECT_FALSE(chunk_generator.next());
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_EQ(0, chunk_generator.size());
+    EXPECT_EQ(0, chunk_generator.complete());
+    EXPECT_TRUE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+}
+
+/*
+ * As a special case, we assume there is no chunking when the chunk size is
+ * zero. Processing a chunk (i.e., execution of "next()"). should progress to
+ * the end of the region.
+ */
+TEST(ChunkGeneratorTest, ChunkSizeZero)
+{
+    ChunkGenerator chunk_generator(0, 64, 0);
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_EQ(64, chunk_generator.size());
+    EXPECT_EQ(0, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+
+    //Process the entire region.
+    EXPECT_FALSE(chunk_generator.next());
+    EXPECT_EQ(0, chunk_generator.addr());
+    EXPECT_EQ(0, chunk_generator.size());
+    EXPECT_EQ(0, chunk_generator.complete());
+    EXPECT_TRUE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+}
+
+/*
+ * A test to ensure a non-zero start functions correctly.
+ */
+TEST(ChunkGeneratorTest, StartAtNonZero)
+{
+    ChunkGenerator chunk_generator(4, 32, 8); //End address: 36.
+    EXPECT_EQ(4, chunk_generator.addr());
+    EXPECT_EQ(4, chunk_generator.size());
+    EXPECT_EQ(0, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_FALSE(chunk_generator.last());
+
+    /*
+     * As the starting position is 4, moving to the next bit should move to
+     * 8 (i.e., process the remainder of the first chunk in the region).
+     */
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(8, chunk_generator.addr());
+    EXPECT_EQ(8, chunk_generator.size());
+    EXPECT_EQ(4, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_FALSE(chunk_generator.last());
+
+    // Process the rest of the region.
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(16, chunk_generator.addr());
+    EXPECT_EQ(8, chunk_generator.size());
+    EXPECT_EQ(12, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_FALSE(chunk_generator.last());
+
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(24, chunk_generator.addr());
+    EXPECT_EQ(8, chunk_generator.size());
+    EXPECT_EQ(20, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_FALSE(chunk_generator.last());
+
+    // The last chunk is also only 4 bytes.
+    EXPECT_TRUE(chunk_generator.next());
+    EXPECT_EQ(32, chunk_generator.addr());
+    EXPECT_EQ(4, chunk_generator.size());
+    EXPECT_EQ(28, chunk_generator.complete());
+    EXPECT_FALSE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+
+    EXPECT_FALSE(chunk_generator.next());
+    EXPECT_EQ(32, chunk_generator.addr());
+    EXPECT_EQ(0, chunk_generator.size());
+    EXPECT_EQ(28, chunk_generator.complete());
+    EXPECT_TRUE(chunk_generator.done());
+    EXPECT_TRUE(chunk_generator.last());
+}
\ No newline at end of file