Add "host-gateway" to tests for extra_hosts / --add-host

67ebcd6dcf added an exception for
the "host-gateway" magic value to the validation rules, but didn't
add thise value to any of the tests.

This patch adds the magic value to tests, to verify the validation
is skipped for this magic value.

Note that validation on the client side is "optional" and mostly
done to provide a more user-friendly error message for regular
values (IP-addresses).

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/compose/loader/full-example.yml

@@ -140,9 +140,11 @@ services:
     # extra_hosts:
     #   somehost: "162.242.195.82"
     #   otherhost: "50.31.209.229"
+    #   host.docker.internal: "host-gateway"
     extra_hosts:
       - "somehost:162.242.195.82"
       - "otherhost:50.31.209.229"
+      - "host.docker.internal:host-gateway"
 
     hostname: foo
 

cli/compose/loader/full-struct_test.go

@@ -144,6 +144,7 @@ func services(workingDir, homeDir string) []types.ServiceConfig {
 			ExtraHosts: []string{
 				"somehost:162.242.195.82",
 				"otherhost:50.31.209.229",
+				"host.docker.internal:host-gateway",
 			},
 			Extras: map[string]interface{}{
 				"x-bar": "baz",
@@ -626,6 +627,7 @@ services:
     extra_hosts:
     - somehost:162.242.195.82
     - otherhost:50.31.209.229
+    - host.docker.internal:host-gateway
     hostname: foo
     healthcheck:
       test:
@@ -1135,7 +1137,8 @@ func fullExampleJSON(workingDir string) string {
       ],
       "extra_hosts": [
         "somehost:162.242.195.82",
-        "otherhost:50.31.209.229"
+        "otherhost:50.31.209.229",
+        "host.docker.internal:host-gateway"
       ],
       "hostname": "foo",
       "healthcheck": {

cli/compose/loader/loader_test.go

@@ -1276,11 +1276,13 @@ services:
     extra_hosts:
       "zulu": "162.242.195.82"
       "alpha": "50.31.209.229"
+      "host.docker.internal": "host-gateway"
 `)
 	assert.NilError(t, err)
 
 	expected := types.HostsList{
 		"alpha:50.31.209.229",
+		"host.docker.internal:host-gateway",
 		"zulu:162.242.195.82",
 	}
 
@@ -1298,6 +1300,7 @@ services:
       - "zulu:162.242.195.82"
       - "alpha:50.31.209.229"
       - "zulu:ff02::1"
+      - "host.docker.internal:host-gateway"
 `)
 	assert.NilError(t, err)
 
@@ -1305,6 +1308,7 @@ services:
 		"zulu:162.242.195.82",
 		"alpha:50.31.209.229",
 		"zulu:ff02::1",
+		"host.docker.internal:host-gateway",
 	}
 
 	assert.Assert(t, is.Len(config.Services, 1))