added AST feature and test case

generate/modfyGenerate.go

@@ -0,0 +1,49 @@
+package generate
+
+import (
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"os"
+)
+
+
+// GetASTGoFile Gets AST of the Go file provided
+func (np *NewProject)GetASTGoFile() error{
+	fset := token.NewFileSet()
+	node, err := parser.ParseFile(fset, np.FileNameAST, nil, parser.ParseComments)
+	if err != nil {
+		return err
+	}
+	//Write Token information to the struct
+	np.Token = fset
+	// Write AST information the struct
+	np.AST = node
+	return nil
+}
+
+// ChangeImports Changes import of the AST
+func (np *NewProject)ChangeImports(CurrentImport string,ChangedImport string) error {
+	// Iterating through the loop and changing the appropriate import
+	for i, spec := range np.AST.Imports {
+		// If the current import is found then change it
+		if spec.Path.Value == "\"" + CurrentImport + "\"" {
+			np.AST.Imports[i].Path.Value = "\"" + ChangedImport + "\""
+		}
+	}
+	return nil
+}
+
+// WriteGoAst Write changed imports back to the AST
+func (np *NewProject)WriteGoAst() error {
+	// write new AST to file
+	f, err := os.Create(np.FileNameAST)
+	if err != nil {
+		return nil
+	}
+	defer f.Close()
+	if err := printer.Fprint(f, np.Token, np.AST); err != nil {
+		return err
+	}
+	return nil
+}