Added more tests

src/build/Function.go

@@ -113,17 +113,17 @@ func (f *Function) CompileInstruction(line token.List) error {
 		return nil
 	}
 
-	if line[0].Kind == token.Identifier {
-		if len(line) < 2 {
-			return fmt.Errorf("error to be implemented")
-		}
+	if len(line) < 2 {
+		return errors.New(&errors.InvalidInstruction{Instruction: line[0].Text()}, f.File, line[0].Position)
+	}
 
+	if line[0].Kind == token.Identifier {
 		if line[1].Kind == token.Define {
 			name := line[0].Text()
 			value := line[2:]
 
 			if len(value) == 0 {
-				return errors.New(errors.MissingAssignmentValue, f.File, line[1].After())
+				return errors.New(errors.MissingAssignValue, f.File, line[1].After())
 			}
 
 			if config.Verbose {

src/errors/CompileErrors.go

@@ -1,5 +1,6 @@
 package errors
 
 var (
-	MissingAssignmentValue = &Base{"Missing assignment value"}
+	InvalidStatement   = &Base{"Invalid statement"}
+	MissingAssignValue = &Base{"Missing assignment value"}
 )

src/errors/InvalidInstruction.go

@@ -0,0 +1,13 @@
+package errors
+
+import "fmt"
+
+// InvalidInstruction error is created when an instruction is not valid.
+type InvalidInstruction struct {
+	Instruction string
+}
+
+// Error generates the string representation.
+func (err *InvalidInstruction) Error() string {
+	return fmt.Sprintf("Invalid instruction '%s'", err.Instruction)
+}