Support running test with reader

python/paddle/fluid/layers/io.py

@@ -259,7 +259,9 @@ def reset():
     return reader
 
 
-def _copy_reader_var_(block, var):
+def _copy_reader_var_(block, var, newname=None):
+    if newname == None:
+        newname = var.name
     new_var = block.create_var(name=var.name, type=core.VarDesc.VarType.READER)
     new_var.desc.set_shapes(var.desc.shapes())
     new_var.desc.set_dtypes(var.desc.dtypes())
@@ -689,3 +691,85 @@ def load(out, file_path, load_as_fp16=None):
     if load_as_fp16 is not None:
         attrs['load_as_fp16'] = load_as_fp16
     helper.append_op(type="load", inputs={}, output={"Out": out}, args=attrs)
+
+
+def _is_reader_op(op, block):
+    if "Out" in op.output_names:
+        reader_out = block.vars[op.output("Out")[0]]
+        if reader_out.type == core.VarDesc.VarType.READER:
+            return True
+    return False
+
+
+def get_test_program(filelist, program=None, startup_program=None):
+    """
+    Transpile current train program to a program to read test dataset
+    if the program is using reader ops like "open_files_op".
+    """
+    if program == None:
+        program = default_main_program()
+    if startup_program == None:
+        startup_program = default_startup_program()
+
+    # 1. find out the orignal reader var name
+    # open_files_var = None
+    # train_open_files_op = None
+    startup_reader_op_list = []
+
+    for op in startup_program.global_block().ops:
+        if _is_reader_op(op, startup_program.global_block()):
+            startup_reader_op_list.append(op)
+
+    if len(startup_reader_op_list) == 0:
+        return program
+
+    root_reader_op = startup_reader_op_list[0]
+
+    # 2. add operators to startup to read open and read test data files
+    for op in startup_reader_op_list:
+        orig_var_name = op.output("Out")[0]
+        orig_var = startup_program.global_block().vars[orig_var_name]
+        new_test_var = _copy_reader_var_(
+            startup_program.global_block(),
+            orig_var,
+            newname=orig_var_name + "_test")
+
+        # for open_files like operators have no input.
+        inputs = None
+        if "UnderlyingReader" in op.input_names:
+            orig_input_var_name = op.input("UnderlyingReader")[0]
+            orig_input_var = startup_program.global_block().vars[
+                orig_input_var_name]
+            new_input_var = _copy_reader_var_(
+                startup_program.global_block(),
+                orig_input_var,
+                newname=orig_input_var_name + "_test")
+            inputs = {"UnderlyingReader": new_input_var}
+        test_op = startup_program.global_block().append_op(
+            type=op.type,
+            inputs=inputs,
+            outputs={'Out': [new_test_var]},
+            attrs=op.attrs)
+        # root reader op's filelist attr for read test files
+        if op.type == root_reader_op.type:
+            test_op.set_attr("file_names", filelist)
+        if op.type == "create_multi_pass_reader":
+            test_op.set_attr("pass_num", 1)
+
+    # 3. rename reader vars in inference program to different name
+    #    to avoid read from train data.
+    origname = root_reader_op.output("Out")[0]
+    newname = origname + "_test"
+    program.global_block().rename_var(str(origname), str(newname))
+    for op in program.global_block().ops:
+        if _is_reader_op(op, program.global_block()):
+            origname = op.output("Out")[0]
+            newname = origname + "_test"
+            program.global_block().rename_var(str(origname), str(newname))
+
+        if op.type == "create_multi_pass_reader":
+            op.set_attr("pass_num", 1)
+
+    program.sync_with_cpp()
+
+    return program