implement get_hosted_zone_count() api (#4814)

docs/docs/services/route53.rst

@@ -64,7 +64,7 @@ route53
 - [ ] get_health_check_last_failure_reason
 - [ ] get_health_check_status
 - [X] get_hosted_zone
-- [ ] get_hosted_zone_count
+- [X] get_hosted_zone_count
 - [ ] get_hosted_zone_limit
 - [X] get_query_logging_config
   Return query logging config, if it exists.

moto/route53/models.py

@@ -498,6 +498,9 @@ class Route53Backend(BaseBackend):
             raise NoSuchHostedZone(id_)
         return the_zone
 
+    def get_hosted_zone_count(self):
+        return len(self.list_hosted_zones())
+
     def get_hosted_zone_by_name(self, name):
         for zone in self.list_hosted_zones():
             if zone.name == name:

moto/route53/responses.py

@@ -93,6 +93,12 @@ class Route53(BaseResponse):
         template = Template(LIST_HOSTED_ZONES_BY_VPC_RESPONSE)
         return 200, headers, template.render(zones=zones, xmlns=XMLNS)
 
+    def get_hosted_zone_count_response(self, request, full_url, headers):
+        self.setup_class(request, full_url, headers)
+        num_zones = route53_backend.get_hosted_zone_count()
+        template = Template(GET_HOSTED_ZONE_COUNT_RESPONSE)
+        return 200, headers, template.render(zone_count=num_zones, xmlns=XMLNS)
+
     @error_handler
     def get_or_delete_hostzone_response(self, request, full_url, headers):
         self.setup_class(request, full_url, headers)
@@ -414,6 +420,11 @@ DELETE_HOSTED_ZONE_RESPONSE = """<DeleteHostedZoneResponse xmlns="https://route5
    </ChangeInfo>
 </DeleteHostedZoneResponse>"""
 
+GET_HOSTED_ZONE_COUNT_RESPONSE = """<GetHostedZoneCountResponse> xmlns="https://route53.amazonaws.com/doc/2012-12-12/">
+   <HostedZoneCount>{{ zone_count }}</HostedZoneCount>
+</GetHostedZoneCountResponse>"""
+
+
 GET_HOSTED_ZONE_RESPONSE = """<GetHostedZoneResponse xmlns="https://route53.amazonaws.com/doc/2012-12-12/">
    <HostedZone>
       <Id>/hostedzone/{{ zone.id }}</Id>

moto/route53/urls.py

@@ -18,6 +18,7 @@ url_paths = {
     r"{0}/(?P<api_version>[\d_-]+)/hostedzone/(?P<zone_id>[^/]+)/rrset/?$": Route53().rrset_response,
     r"{0}/(?P<api_version>[\d_-]+)/hostedzonesbyname": Route53().list_hosted_zones_by_name_response,
     r"{0}/(?P<api_version>[\d_-]+)/hostedzonesbyvpc": Route53().list_hosted_zones_by_vpc_response,
+    r"{0}/(?P<api_version>[\d_-]+)/hostedzonecount": Route53().get_hosted_zone_count_response,
     r"{0}/(?P<api_version>[\d_-]+)/healthcheck": Route53().health_check_response,
     r"{0}/(?P<api_version>[\d_-]+)/healthcheck/(?P<health_check_id>[^/]+)$": Route53().health_check_response,
     r"{0}/(?P<api_version>[\d_-]+)/tags/healthcheck/(?P<zone_id>[^/]+)$": tag_response1,

tests/test_route53/test_route53.py

@@ -61,6 +61,57 @@ def test_delete_hosted_zone():
     res.should.have.length_of(1)
 
 
+@mock_route53
+def test_get_hosted_zone_count_no_zones():
+    conn = boto3.client("route53", region_name="us-east-1")
+    zone_count = conn.get_hosted_zone_count()
+    zone_count.should.have.key("HostedZoneCount")
+    isinstance(zone_count["HostedZoneCount"], int).should.be.true
+    zone_count["HostedZoneCount"].should.be.equal(0)
+
+
+@mock_route53
+def test_get_hosted_zone_count_one_zone():
+    conn = boto3.client("route53", region_name="us-east-1")
+    zone = "a"
+    zone_name = f"test.{zone}.com."
+    conn.create_hosted_zone(
+        Name=zone_name,
+        CallerReference=str(hash("foo")),
+        HostedZoneConfig=dict(PrivateZone=False, Comment=f"test {zone} com"),
+    )
+    zone_count = conn.get_hosted_zone_count()
+    zone_count.should.have.key("HostedZoneCount")
+    isinstance(zone_count["HostedZoneCount"], int).should.be.true
+    zone_count["HostedZoneCount"].should.be.equal(1)
+
+
+@mock_route53
+def test_get_hosted_zone_count_many_zones():
+    conn = boto3.client("route53", region_name="us-east-1")
+    zones = {}
+    zone_indexes = []
+    for char in range(ord("a"), ord("d") + 1):
+        for char2 in range(ord("a"), ord("z") + 1):
+            zone_indexes.append(f"{chr(char)}{chr(char2)}")
+
+    # Create 100-ish zones and make sure we get 100 back.  This works
+    # for 702 zones {a..zz}, but seemed a needless waste of
+    # time/resources.
+    for zone in zone_indexes:
+        zone_name = f"test.{zone}.com."
+        zones[zone] = conn.create_hosted_zone(
+            Name=zone_name,
+            CallerReference=str(hash("foo")),
+            HostedZoneConfig=dict(PrivateZone=False, Comment=f"test {zone} com"),
+        )
+    zone_count = conn.get_hosted_zone_count()
+    zone_count.should.have.key("HostedZoneCount")
+    isinstance(zone_count["HostedZoneCount"], int).should.be.true
+    zone_count["HostedZoneCount"].shouldnt.be.equal(0)
+    zone_count["HostedZoneCount"].should.be.equal(len(zone_indexes))
+
+
 @mock_route53
 def test_get_unknown_hosted_zone():
     conn = boto3.client("route53", region_name="us-east-1")