Add more unit tests for index_read and index_write (facebookresearch#4068)

Summary:
Pull Request resolved: facebookresearch#4068

Adds missing coverage for index_write and index_read

Reviewed By: asadoughi

Differential Revision: D66846063

fbshipit-source-id: 68686318ecce64804425502a425a06f510fb5df8

Author: Michael Norris

tests/test_io.py

@@ -12,8 +12,14 @@
 import sys
 import pickle
 from multiprocessing.pool import ThreadPool
+from common_faiss_tests import get_dataset_2
 
 
+d = 32
+nt = 2000
+nb = 1000
+nq = 200
+
 class TestIOVariants(unittest.TestCase):
 
     def test_io_error(self):
@@ -338,6 +344,113 @@ def test_read_vector_transform(self):
                 os.unlink(fname)
 
 
+class Test_IO_PQ(unittest.TestCase):
+    """
+    test read and write PQ.
+    """
+    def test_io_pq(self):
+        xt, xb, xq = get_dataset_2(d, nt, nb, nq)
+        index = faiss.IndexPQ(d, 4, 4)
+        index.train(xt)
+
+        fd, fname = tempfile.mkstemp()
+        os.close(fd)
+
+        try:
+            faiss.write_ProductQuantizer(index.pq, fname)
+
+            read_pq = faiss.read_ProductQuantizer(fname)
+
+            self.assertEqual(index.pq.M, read_pq.M)
+            self.assertEqual(index.pq.nbits, read_pq.nbits)
+            self.assertEqual(index.pq.dsub, read_pq.dsub)
+            self.assertEqual(index.pq.ksub, read_pq.ksub)
+            np.testing.assert_array_equal(
+                faiss.vector_to_array(index.pq.centroids),
+                faiss.vector_to_array(read_pq.centroids)
+            )
+
+        finally:
+            if os.path.exists(fname):
+                os.unlink(fname)
+
+
+class Test_IO_IndexLSH(unittest.TestCase):
+    """
+    test read and write IndexLSH.
+    """
+    def test_io_lsh(self):
+        xt, xb, xq = get_dataset_2(d, nt, nb, nq)
+        index_lsh = faiss.IndexLSH(d, 32, True, True)
+        index_lsh.train(xt)
+        index_lsh.add(xb)
+        D, I = index_lsh.search(xq, 10)
+
+        fd, fname = tempfile.mkstemp()
+        os.close(fd)
+
+        try:
+            faiss.write_index(index_lsh, fname)
+
+            reader = faiss.BufferedIOReader(
+                faiss.FileIOReader(fname), 1234)
+            read_index_lsh = faiss.read_index(reader)
+            # Delete reader to prevent [WinError 32] The process cannot
+            # access the file because it is being used by another process
+            del reader
+
+            self.assertEqual(index_lsh.d, read_index_lsh.d)
+            np.testing.assert_array_equal(
+                faiss.vector_to_array(index_lsh.codes),
+                faiss.vector_to_array(read_index_lsh.codes)
+            )
+            D_read, I_read = read_index_lsh.search(xq, 10)
+
+            np.testing.assert_array_equal(D, D_read)
+            np.testing.assert_array_equal(I, I_read)
+
+        finally:
+            if os.path.exists(fname):
+                os.unlink(fname)
+
+
+class Test_IO_IndexIVFSpectralHash(unittest.TestCase):
+    """
+    test read and write IndexIVFSpectralHash.
+    """
+    def test_io_ivf_spectral_hash(self):
+        nlist = 1000
+        xt, xb, xq = get_dataset_2(d, nt, nb, nq)
+        quantizer = faiss.IndexFlatL2(d)
+        index = faiss.IndexIVFSpectralHash(quantizer, d, nlist, 8, 1.0)
+        index.train(xt)
+        index.add(xb)
+        D, I = index.search(xq, 10)
+
+        fd, fname = tempfile.mkstemp()
+        os.close(fd)
+
+        try:
+            faiss.write_index(index, fname)
+
+            reader = faiss.BufferedIOReader(
+                faiss.FileIOReader(fname), 1234)
+            read_index = faiss.read_index(reader)
+            del reader
+
+            self.assertEqual(index.d, read_index.d)
+            self.assertEqual(index.nbit, read_index.nbit)
+            self.assertEqual(index.period, read_index.period)
+            self.assertEqual(index.threshold_type, read_index.threshold_type)
+
+            D_read, I_read = read_index.search(xq, 10)
+            np.testing.assert_array_equal(D, D_read)
+            np.testing.assert_array_equal(I, I_read)
+
+        finally:
+            if os.path.exists(fname):
+                os.unlink(fname)
+
 class TestIVFPQRead(unittest.TestCase):
     def test_reader(self):
         d, n = 32, 1000