Add test to read empty file (#512)

* Add test to read empty file

* Add assert statements

Author: kylebarron

tests/data/empty.parquet

@@ -1,3 +1,4 @@
+import pandas as pd
 import pyarrow as pa
 import pyarrow.feather as feather
 import pyarrow.parquet as pq
@@ -30,9 +31,14 @@ def write_data(table):
             )
 
 
+def write_empty_table():
+    pd.DataFrame().to_parquet("empty.parquet")
+
+
 def main():
     table = create_data()
     write_data(table)
+    write_empty_table()
 
 
 if __name__ == "__main__":

tests/data/generate_data.py

@@ -77,3 +77,15 @@ it("error produced trying to read file with arrayBuffer", (t) => {
     );
   }
 });
+
+it("reads empty file", async (t) => {
+  const dataPath = `${dataDir}/empty.parquet`;
+  const buffer = readFileSync(dataPath);
+  const arr = new Uint8Array(buffer);
+  const table = tableFromIPC(wasm.readParquet(arr).intoIPCStream());
+
+  expect(table.schema.fields.length).toStrictEqual(0);
+  expect(table.numRows).toStrictEqual(0);
+  expect(table.numCols).toStrictEqual(0);
+  // console.log("empty table schema", table.schema);
+});