feat: Added indent filter (#188)

Tests/StencilTests/FilterSpec.swift

@@ -244,4 +244,30 @@ func testFilter() {
 
   }
 
+
+  describe("indent filter") {
+    $0.it("indents content") {
+      let template = Template(templateString: "{{ value|indent:2 }}")
+      let result = try template.render(Context(dictionary: ["value": "One\nTwo"]))
+      try expect(result) == "One\n  Two"
+    }
+
+    $0.it("can indent with arbitrary character") {
+      let template = Template(templateString: "{{ value|indent:2,\"\t\" }}")
+      let result = try template.render(Context(dictionary: ["value": "One\nTwo"]))
+      try expect(result) == "One\n\t\tTwo"
+    }
+
+    $0.it("can indent first line") {
+      let template = Template(templateString: "{{ value|indent:2,\" \",true }}")
+      let result = try template.render(Context(dictionary: ["value": "One\nTwo"]))
+      try expect(result) == "  One\n  Two"
+    }
+
+    $0.it("does not indent empty lines") {
+      let template = Template(templateString: "{{ value|indent }}")
+      let result = try template.render(Context(dictionary: ["value": "One\n\n\nTwo\n\n"]))
+      try expect(result) == "One\n\n\n    Two\n\n"
+    }
+  }
 }

Tests/StencilTests/FilterTagSpec.swift

@@ -21,5 +21,14 @@ func testFilterTag() {
       try expect(try template.render()).toThrow()
     }
 
+    $0.it("can render filters with arguments") {
+      let ext = Extension()
+      ext.registerFilter("split", filter: {
+        return ($0 as! String).components(separatedBy: $1[0] as! String)
+      })
+      let env = Environment(extensions: [ext])
+      let result = try env.renderTemplate(string: "{% filter split:\",\"|join:\";\"  %}{{ items|join:\",\" }}{% endfilter %}", context: ["items": [1, 2]])
+      try expect(result) == "1;2"
+    }
   }
 }

Tests/StencilTests/VariableSpec.swift

@@ -71,6 +71,13 @@ func testVariable() {
       try expect(result) == 3.14
     }
 
+    $0.it("can resolve boolean literal") {
+      try expect(Variable("true").resolve(context) as? Bool) == true
+      try expect(Variable("false").resolve(context) as? Bool) == false
+      try expect(Variable("0").resolve(context) as? Int) == 0
+      try expect(Variable("1").resolve(context) as? Int) == 1
+    }
+
     $0.it("can resolve a string variable") {
       let variable = Variable("name")
       let result = try variable.resolve(context) as? String