feat(text): add template support

resolves #884

docs/docs/segment-text.md

@@ -25,5 +25,19 @@ Display text.
 ## Properties
 
 - text: `string` - text/icon to display. Accepts [coloring foreground][coloring] just like `prefix` and `postfix`.
+Powered by go [text/template][go-text-template] templates extended with [sprig][sprig] utilizing the
+properties below.
+
+## Template Properties
+
+- `.Root`: `boolean` - is the current user root/admin or not
+- `.Path`: `string` - the current working directory
+- `.Folder`: `string` - the current working folder
+- `.Shell`: `string` - the current shell name
+- `.User`: `string` - the current user name
+- `.Host`: `string` - the host name
+- `.Env.VarName`: `string` - Any environment variable where `VarName` is the environment variable name
 
 [coloring]: /docs/configure#colors
+[go-text-template]: https://golang.org/pkg/text/template/
+[sprig]: https://masterminds.github.io/sprig/

src/segment_text.go

@@ -16,7 +16,13 @@ func (t *text) enabled() bool {
 
 func (t *text) string() string {
 	textProperty := t.props.getString(TextProperty, "!!text property not defined!!")
-	return textProperty
+	template := &textTemplate{
+		Template: textProperty,
+		Context:  t,
+		Env:      t.env,
+	}
+	textOutput := template.renderPlainContextTemplate(nil)
+	return textOutput
 }
 
 func (t *text) init(props *properties, env environmentInfo) {

src/segment_text_test.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTextSegment(t *testing.T) {
+	cases := []struct {
+		Case           string
+		ExpectedString string
+		Text           string
+	}{
+		{Case: "standard text", ExpectedString: "hello", Text: "hello"},
+		{Case: "template text with env var", ExpectedString: "hello world", Text: "{{ .Env.HELLO }} world"},
+		{Case: "template text with shell name", ExpectedString: "hello world from terminal", Text: "{{ .Env.HELLO }} world from {{ .Shell }}"},
+		{Case: "template text with folder", ExpectedString: "hello world in posh", Text: "{{ .Env.HELLO }} world in {{ .Folder }}"},
+		{Case: "template text with user", ExpectedString: "hello Posh", Text: "{{ .Env.HELLO }} {{ .User }}"},
+	}
+
+	for _, tc := range cases {
+		env := new(MockedEnvironment)
+		env.On("getcwd", nil).Return("/usr/home/posh")
+		env.On("homeDir", nil).Return("/usr/home")
+		env.On("getPathSeperator", nil).Return("/")
+		env.On("isRunningAsRoot", nil).Return(true)
+		env.On("getShellName", nil).Return("terminal")
+		env.On("getenv", "HELLO").Return("hello")
+		env.On("getCurrentUser", nil).Return("Posh")
+		env.On("getHostName", nil).Return("MyHost", nil)
+		props := &properties{
+			values: map[Property]interface{}{
+				TextProperty: tc.Text,
+			},
+		}
+		txt := &text{
+			env:   env,
+			props: props,
+		}
+		assert.Equal(t, tc.ExpectedString, txt.string(), tc.Case)
+	}
+}