charm: Add config.Convert()

charm/config_test.go

Index: charm/config_test.go
=== modified file 'charm/config_test.go'
--- charm/config_test.go	2013-02-11 05:51:12 +0000
+++ charm/config_test.go	2013-02-27 08:18:52 +0000
@@ -189,3 +189,68 @@
 	c.Assert(output, IsNil)
 	c.Assert(err, ErrorMatches, `Unknown configuration option: "bad"`)
 }
+
+var convertTests = []struct {
+	summary string
+	input   map[string]interface{}
+	expect  map[string]interface{}
+	err     string
+}{{
+	// Schema defaults are ignored.
+	summary: "valid strings",
+	input: map[string]interface{}{
+		"title":   "Helpful Title",
+		"outlook": "Peachy",
+	},
+	expect: map[string]interface{}{
+		"title":   "Helpful Title",
+		"outlook": "Peachy",
+	},
+}, {
+	// Integers are always int64 in YAML, where the input is usually coming from.
+	summary: "valid integers and floats",
+	input: map[string]interface{}{
+		"agility-ratio": 0.5,
+		"skill-level":   int64(7),
+	},
+	expect: map[string]interface{}{
+		"agility-ratio": 0.5,
+		"skill-level":   int64(7),
+	},
+}, {
+	summary: "valid booleans",
+	input:   map[string]interface{}{"reticulate-splines": true},
+	expect:  map[string]interface{}{"reticulate-splines": true},
+}, {
+	summary: "invalid type error with floats",
+	input:   map[string]interface{}{"agility-ratio": "bar"},
+	err:     `unexpected type in service configuration "agility-ratio"="bar"; expected float`,
+}, {
+	summary: "invalid type error with integers",
+	input:   map[string]interface{}{"skill-level": "foo"},
+	err:     `unexpected type in service configuration "skill-level"="foo"; expected int`,
+}, {
+	summary: "invalid type error with booleans",
+	input:   map[string]interface{}{"reticulate-splines": "maybe"},
+	err:     `unexpected type in service configuration "reticulate-splines"="maybe"; expected boolean`,
+}, {
+	summary: "with value not in the schema (ignored)",
+	input:   map[string]interface{}{"bad": "value"},
+	expect:  map[string]interface{}{},
+}}
+
+func (s *ConfigSuite) TestConvert(c *C) {
+	config, err := charm.ReadConfig(bytes.NewBuffer([]byte(sampleConfig)))
+	c.Assert(err, IsNil)
+
+	for i, t := range convertTests {
+		c.Logf("test %d: %s", i, t.summary)
+		output, err := config.Convert(t.input)
+		if t.err != "" {
+			c.Assert(err, ErrorMatches, t.err)
+		} else {
+			c.Assert(err, IsNil)
+			c.Assert(output, DeepEquals, t.expect)
+		}
+	}
+}