From d9378af13add879118a1d004529b811f72c325d6 Mon Sep 17 00:00:00 2001
From: Peter Lamut <plamut@users.noreply.github.com>
Date: Wed, 28 Jul 2021 17:18:18 +0200
Subject: [PATCH] fix: `insert_rows()` accepts float column values as strings
 again (#824)

---
 google/cloud/bigquery/_helpers.py | 12 +++++++-----
 tests/unit/test__helpers.py       | 24 ++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/google/cloud/bigquery/_helpers.py b/google/cloud/bigquery/_helpers.py
index bf0f80e22..0a1f71444 100644
--- a/google/cloud/bigquery/_helpers.py
+++ b/google/cloud/bigquery/_helpers.py
@@ -19,6 +19,7 @@
 import decimal
 import math
 import re
+from typing import Union
 
 from google.cloud._helpers import UTC
 from google.cloud._helpers import _date_from_iso8601_date
@@ -338,14 +339,15 @@ def _int_to_json(value):
     return value
 
 
-def _float_to_json(value):
+def _float_to_json(value) -> Union[None, str, float]:
     """Coerce 'value' to an JSON-compatible representation."""
     if value is None:
         return None
-    elif math.isnan(value) or math.isinf(value):
-        return str(value)
-    else:
-        return float(value)
+
+    if isinstance(value, str):
+        value = float(value)
+
+    return str(value) if (math.isnan(value) or math.isinf(value)) else float(value)
 
 
 def _decimal_to_json(value):
diff --git a/tests/unit/test__helpers.py b/tests/unit/test__helpers.py
index af026ccbe..f8d00e67d 100644
--- a/tests/unit/test__helpers.py
+++ b/tests/unit/test__helpers.py
@@ -690,21 +690,45 @@ def _call_fut(self, value):
     def test_w_none(self):
         self.assertEqual(self._call_fut(None), None)
 
+    def test_w_non_numeric(self):
+        with self.assertRaises(TypeError):
+            self._call_fut(object())
+
+    def test_w_integer(self):
+        result = self._call_fut(123)
+        self.assertIsInstance(result, float)
+        self.assertEqual(result, 123.0)
+
     def test_w_float(self):
         self.assertEqual(self._call_fut(1.23), 1.23)
 
+    def test_w_float_as_string(self):
+        self.assertEqual(self._call_fut("1.23"), 1.23)
+
     def test_w_nan(self):
         result = self._call_fut(float("nan"))
         self.assertEqual(result.lower(), "nan")
 
+    def test_w_nan_as_string(self):
+        result = self._call_fut("NaN")
+        self.assertEqual(result.lower(), "nan")
+
     def test_w_infinity(self):
         result = self._call_fut(float("inf"))
         self.assertEqual(result.lower(), "inf")
 
+    def test_w_infinity_as_string(self):
+        result = self._call_fut("inf")
+        self.assertEqual(result.lower(), "inf")
+
     def test_w_negative_infinity(self):
         result = self._call_fut(float("-inf"))
         self.assertEqual(result.lower(), "-inf")
 
+    def test_w_negative_infinity_as_string(self):
+        result = self._call_fut("-inf")
+        self.assertEqual(result.lower(), "-inf")
+
 
 class Test_decimal_to_json(unittest.TestCase):
     def _call_fut(self, value):