SearchAPI - AND query returns no documents

[scragraham]

Summary
When running a search with an AND query, I epxected to get 2 documents back, instead an empty document list is returned.

Steps to Reproduce
Input json:

{"index": "index-1", "documents": [
        {
          "id": "a",
          "text1": "hello world",
          "text2": "testing search api and world"
        },
        {
          "id": "b",
          "anotherText": "There is also a corresponding asynchronous method, "
        },
        {
          "id": "c",
          "text3": "This string also contains the word world and api"
        },
        {
          "id": "firstdate",
          "date_entered": "2018-12-12",
          "text4": "This is a test of the national broadcasting system"
        },
        {
          "id": "seconddate",
          "date_entered": "2019-04-04",
          "text5": "Who are the britons?"
        }
      ]}

UnitTest

  def test_search_query_AND_two_results(self):
    response = self.app.post(
      '/python/search/search',
      json={"index": "index-1", "query": "world AND api"})

    self.assertEquals(response.status_code, 200)
    self.assertIn('documents', response.json())
    documents = response.json()['documents']
    self.assertEquals(len(documents), 2)

Test Failure

======================================================================
FAIL: test_search_query_AND_two_results (tests.search_tests.SearchTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/hawkeye/test-suite/tests/search_tests.py", line 94, in test_search_query_AND_two_results
    self.assertEquals(len(documents), 2)
AssertionError: 0 != 2

Expected
Two documents id: a, id: c

Actual
No documents.

SearchAPI logs

{
    "response": {
        "docs": [],
        "numFound": 0,
        "start": 0
    },
    "responseHeader": {
        "QTime": 10,
        "params": {
            "defType": "edismax",
            "fl": "id _gaeindex_locale hawkeyepython27__index-1_anotherText hawkeyepython27__index-1_date_entered hawkeyepython27__index-1_text1 hawkeyepython27__index-1_text2 hawkeyepython27__index-1_text3 hawkeyepython27__index-1_text4 hawkeyepython27__index-1_text5",
            "pf": "hawkeyepython27__index-1_anotherText hawkeyepython27__index-1_date_entered hawkeyepython27__index-1_text1 hawkeyepython27__index-1_text2 hawkeyepython27__index-1_text3 hawkeyepython27__index-1_text4 hawkeyepython27__index-1_text5",
            "q": "_gaeindex_name:hawkeyepython27__index-1 AND (%22world%22 AND%22api%22)",
            "qf": "hawkeyepython27__index-1_anotherText hawkeyepython27__index-1_date_entered hawkeyepython27__index-1_text1 hawkeyepython27__index-1_text2 hawkeyepython27__index-1_text3 hawkeyepython27__index-1_text4 hawkeyepython27__index-1_text5",
            "rows": "20",
            "start": "0",
            "wt": "json"
        },
        "status": 0
    }
}