Add Comment spec

Sources/HummingbirdMustache/Template+Parser.swift

@@ -62,11 +62,17 @@ extension HBMustacheTemplate {
             case "!":
                 parser.unsafeAdvance()
                 _ = try parseComment(&parser)
+                if parser.current() == "\n" {
+                    parser.unsafeAdvance()
+                }
 
             case ">":
                 parser.unsafeAdvance()
                 let (name, _) = try parseName(&parser)
                 tokens.append(.partial(name))
+                if parser.current() == "\n" {
+                    parser.unsafeAdvance()
+                }
 
             default:
                 let (name, method) = try parseName(&parser)

Tests/HummingbirdMustacheTests/SpecTests.swift

@@ -0,0 +1,114 @@
+import HummingbirdMustache
+import XCTest
+
+/// Mustache spec tests. These are the formal standard for Mustache. More details
+/// can be found at https://github.com/mustache/spec
+
+func test(_ object: Any, _ template: String, _ expected: String) throws {
+    let template = try HBMustacheTemplate(string: template)
+    let result = template.render(object)
+    XCTAssertEqual(result, expected)
+}
+
+//MARK: Comments
+
+final class SpecCommentsTests: XCTestCase {
+
+    func testInline() throws {
+        let object = {}
+        let template = "12345{{! Comment Block! }}67890"
+        let expected = "1234567890"
+        try test(object, template, expected)
+    }
+
+    func testMultiline() throws {
+        let object = {}
+        let template = """
+        12345{{!
+                This is a
+                multi-line comment...
+              }}67890
+        """
+        let expected = "1234567890"
+        try test(object, template, expected)
+    }
+
+    func testStandalone() throws {
+        let object = {}
+        let template = """
+        Begin.
+        {{! Comment Block! }}
+        End.
+        """
+        let expected = """
+        Begin.
+        End.
+        """
+        try test(object, template, expected)
+    }
+
+    func testIndentedStandalone() throws {
+        let object = {}
+        let template = """
+        Begin.
+          {{! Comment Block! }}
+        End.
+        """
+        let expected = """
+        Begin.
+        End.
+        """
+        try test(object, template, expected)
+    }
+
+    func testStandaloneLineEndings() throws {
+        let object = {}
+        let template = "\r\n{{! Standalone Comment }}\r\n"
+        let expected = "\r\n"
+        try test(object, template, expected)
+    }
+
+    func testStandaloneWithoutPreviousLine() throws {
+        let object = {}
+        let template = "  {{! I'm Still Standalone }}\n!"
+        let expected = "!"
+        try test(object, template, expected)
+    }
+
+    func testStandaloneWithoutNewLine() throws {
+        let object = {}
+        let template = "!\n  {{! I'm Still Standalone }}"
+        let expected = "!\n"
+        try test(object, template, expected)
+    }
+
+    func testStandaloneMultiLine() throws {
+        let object = {}
+        let template = """
+        Begin.
+          {{!
+            Something's going on here...
+          }}
+        End.
+        """
+        let expected = """
+        Begin.
+        End.
+        """
+        try test(object, template, expected)
+    }
+
+    func testIndentedInline()  throws {
+        let object = {}
+        let template = "  12 {{! 34 }}\n"
+        let expected = "  12 \n"
+        try test(object, template, expected)
+    }
+
+    func testSurroundingWhitespace()  throws {
+        let object = {}
+        let template = "12345 {{! Comment Block! }} 67890"
+        let expected = "12345  67890"
+        try test(object, template, expected)
+    }
+}