config: check for duplicate inputs

Given two identical paths "x/y" and "x/y", the go-bindata will generate
both assets.

This changes check for duplicate paths in validateInputs and repopulate
the Config.Input with new list.

Fix #37

config.go

@@ -193,14 +193,28 @@ func NewConfig() *Config {
 }
 
 func (c *Config) validateInput() (err error) {
+	uniqPaths := make(map[string]struct{}, len(c.Input))
+	newInputs := make([]InputConfig, 0, len(c.Input))
+
 	for _, input := range c.Input {
+		input.Path = filepath.Clean(input.Path)
+		_, ok := uniqPaths[input.Path]
+		if ok {
+			continue
+		}
 		_, err = os.Lstat(input.Path)
 		if err != nil {
 			return fmt.Errorf("failed to stat input path '%s': %v",
 				input.Path, err)
 		}
+		uniqPaths[input.Path] = struct{}{}
+		newInputs = append(newInputs, input)
 	}
-	return
+	if len(newInputs) == 0 {
+		return ErrNoInput
+	}
+	c.Input = newInputs
+	return nil
 }
 
 //

config_test.go

@@ -14,6 +14,7 @@ func TestValidateInput(t *testing.T) {
 	tests := []struct {
 		desc   string
 		cfg    *Config
+		exp    []InputConfig
 		expErr string
 	}{{
 		desc:   `With empty list`,
@@ -26,22 +27,39 @@ func TestValidateInput(t *testing.T) {
 				Path: "",
 			}},
 		},
-		expErr: `failed to stat input path '': lstat : no such file or directory`,
+		exp: []InputConfig{{
+			Path: ".",
+		}},
 	}, {
 		desc: `With directory not exist`,
 		cfg: &Config{
 			Input: []InputConfig{{
 				Path: "./notexist",
 			}},
 		},
-		expErr: `failed to stat input path './notexist': lstat ./notexist: no such file or directory`,
+		expErr: `failed to stat input path 'notexist': lstat notexist: no such file or directory`,
 	}, {
 		desc: `With file as input`,
 		cfg: &Config{
 			Input: []InputConfig{{
 				Path: "./README.md",
 			}},
 		},
+		exp: []InputConfig{{
+			Path: "README.md",
+		}},
+	}, {
+		desc: `With duplicate inputs`,
+		cfg: &Config{
+			Input: []InputConfig{{
+				Path: "./testdata/in/test.asset",
+			}, {
+				Path: "./testdata/in/test.asset",
+			}},
+		},
+		exp: []InputConfig{{
+			Path: "testdata/in/test.asset",
+		}},
 	}}
 
 	for _, test := range tests {
@@ -52,6 +70,8 @@ func TestValidateInput(t *testing.T) {
 			assert(t, test.expErr, err.Error(), true)
 			continue
 		}
+
+		assert(t, test.exp, test.cfg.Input, true)
 	}
 }