test-ob.el: Fix and enhance tests

* testing/lisp/test-ob.el (test-ob/string-to-number): Fix and
enhance tests.

testing/lisp/test-ob.el

@@ -2120,14 +2120,16 @@ abc
 	  (org-babel-execute-src-block))))))
 
 (ert-deftest test-ob/string-to-number ()
-    (should (=  0   (org-babel--string-to-number "0")))
-    (should (=  1   (org-babel--string-to-number "1")))
-    (should (eq nil (org-babel--string-to-number "000")))
-    (should (eq nil (org-babel--string-to-number "001")))
-    (should (eq nil (org-babel--string-to-number "010")))
-    (should (=  100 (org-babel--string-to-number "100")))
-    (should (=  0.1 (org-babel--string-to-number "0.1")))
-    (should (=  1.0 (org-babel--string-to-number "1.0"))))
+    (should (=  0      (org-babel--string-to-number "0")))
+    (should (=  1      (org-babel--string-to-number "1")))
+    (should (eq nil    (org-babel--string-to-number "1 2")))
+    (should (=  1000.0 (org-babel--string-to-number "1e3")))
+    (should (eq 0      (org-babel--string-to-number "000")))
+    (should (eq 1      (org-babel--string-to-number "001")))
+    (should (eq 10     (org-babel--string-to-number "010")))
+    (should (=  100    (org-babel--string-to-number "100")))
+    (should (=  0.1    (org-babel--string-to-number "0.1")))
+    (should (=  1.0    (org-babel--string-to-number "1.0"))))
 
 (provide 'test-ob)