charm: allow empty string options

charm/config_test.go

 // Copyright 2011, 2012, 2013 Canonical Ltd.
 // Licensed under the AGPLv3, see LICENCE file for details.
 
 package charm_test
 
 import (
         "bytes"
         "fmt"
 
         gc "launchpad.net/gocheck"
@@ skipping 94 matching lines @@
                 "username":           nil,
                 "unknown":            "whatever",
                 "outlook":            "",
                 "skill-level":        5.5,
                 "agility-ratio":      true,
                 "reticulate-splines": "hullo",
         })
         c.Assert(settings, gc.DeepEquals, charm.Settings{
                 "title":    "something valid",
                 "username": nil,
-                "outlook":  nil,
+                "outlook":  "",
         })
 }
 
 func (s *ConfigSuite) TestValidateSettings(c *gc.C) {
         for i, test := range []struct {
                 info   string
                 input  charm.Settings
                 expect charm.Settings
                 err    string
         }{{
@@ skipping 16 matching lines @@
                 },
         }, {
                 info: "correctly-typed values are valid",
                 input: charm.Settings{
                         "outlook":            "stormy",
                         "skill-level":        int64(123),
                         "agility-ratio":      0.5,
                         "reticulate-splines": true,
                 },
         }, {
-                info:   "empty string-typed values become nil",
+                info:   "empty string-typed values stay empty",
                 input:  charm.Settings{"outlook": ""},
-                expect: charm.Settings{"outlook": nil},
+                expect: charm.Settings{"outlook": ""},
         }, {
                 info: "almost-correctly-typed values are valid",
                 input: charm.Settings{
                         "skill-level":   123,
                         "agility-ratio": float32(0.5),
                 },
                 expect: charm.Settings{
                         "skill-level":   int64(123),
                         "agility-ratio": 0.5,
                 },
@@ skipping 107 matching lines @@
         }, {
                 info: "nil values are valid",
                 yaml: `blah:
             outlook: null
             skill-level: null
             agility-ratio: null
             reticulate-splines: null`,
                 key:    "blah",
                 expect: settingsWithNils,
         }, {
-                info: "empty strings are considered nil",
+                info: "empty strings for non-string options are not accepted",
                 yaml: `blah:
             outlook: ""
             skill-level: ""
             agility-ratio: ""
             reticulate-splines: ""`,
-                key:    "blah",
-                expect: settingsWithNils,
+                key: "blah",
+                err: `option "skill-level" expected int, got ""`,
         }, {
                 info: "appropriate strings are valid",
                 yaml: `blah:
             outlook: whatever
             skill-level: "123"
             agility-ratio: "2.22"
             reticulate-splines: "true"`,
                 key:    "blah",
                 expect: settingsWithValues,
         }, {
@@ skipping 24 matching lines @@
                 expect charm.Settings
                 err    string
         }{{
                 info:   "nil map is valid",
                 expect: charm.Settings{},
         }, {
                 info:   "empty map is valid",
                 input:  map[string]string{},
                 expect: charm.Settings{},
         }, {
-                info: "empty strings are nil values",
-                input: map[string]string{
-                        "outlook":            "",
-                        "skill-level":        "",
-                        "agility-ratio":      "",
-                        "reticulate-splines": "",
-                },
-                expect: settingsWithNils,
+                info:   "empty strings for string options are valid",
+                input:  map[string]string{"outlook": ""},
+                expect: charm.Settings{"outlook": ""},
+        }, {
+                info:  "empty strings for non-string options are invalid",
+                input: map[string]string{"skill-level": ""},
+                err:   `option "skill-level" expected int, got ""`,
         }, {
                 info: "strings are converted",
                 input: map[string]string{
                         "outlook":            "whatever",
                         "skill-level":        "123",
                         "agility-ratio":      "2.22",
                         "reticulate-splines": "true",
                 },
                 expect: settingsWithValues,
         }, {
@@ skipping 52 matching lines @@
         assertTypeError("int", "true", "true")
 }
 
 // When an empty config is supplied an error should be returned
 func (s *ConfigSuite) TestEmptyConfigReturnsError(c *gc.C) {
         config := ""
         result, err := charm.ReadConfig(bytes.NewBuffer([]byte(config)))
         c.Assert(result, gc.IsNil)
         c.Assert(err, gc.ErrorMatches, "invalid config: empty configuration")
 }