Designing the Article Model

We will keep the article structure simple with just three fields - Id, Title and Content. This can be represented with a struct as follows:

type article struct {
  ID      int    `json:"id"`
  Title   string `json:"title"`
  Content string `json:"content"`
}

Most applications will use a database to persist the data. To keep things simple, we will keep the list of articles in memory and will initialize the list with two hard-coded articles as follows:

var articleList = []article{
  article{ID: 1, Title: "Article 1", Content: "Article 1 body"},
  article{ID: 2, Title: "Article 2", Content: "Article 2 body"},
}

We will place the above code in a new file named models.article.go. At this stage, we need a function that will return the list of all articles. We will name this function getAllArticles() and place it in the same file. We will also write a test for it. This test will be named TestGetAllArticles and will be placed in the models.article_test.go file.

Let's start by creating the unit test (TestGetAllArticles) for the getAllArticles() function. After creating this unit test, the models.article_test.go file should contain the following code:

// models.article_test.go

package main

import "testing"

// Test the function that fetches all articles
func TestGetAllArticles(t *testing.T) {
  alist := getAllArticles()

  // Check that the length of the list of articles returned is the
  // same as the length of the global variable holding the list
  if len(alist) != len(articleList) {
    t.Fail()
  }

  // Check that each member is identical
  for i, v := range alist {
    if v.Content != articleList[i].Content ||
      v.ID != articleList[i].ID ||
      v.Title != articleList[i].Title {

      t.Fail()
      break
    }
  }
}

This unit test uses the getAllArticles() function to fetch the list of all articles. This test first makes sure that the article list fetched by this function and the article list present in the global variable articleList are identical. It then loops over the article list to verify that each article is identical. The test fails if either of these two checks fail.

Once we have written the test, we can proceed to write the actual code. Themodels.article.go file should contain the following code:

// models.article.go

package main

type article struct {
  ID      int    `json:"id"`
  Title   string `json:"title"`
  Content string `json:"content"`
}

// For this demo, we're storing the article list in memory
// In a real application, this list will most likely be fetched
// from a database or from static files
var articleList = []article{
  article{ID: 1, Title: "Article 1", Content: "Article 1 body"},
  article{ID: 2, Title: "Article 2", Content: "Article 2 body"},
}

// Return a list of all the articles
func getAllArticles() []article {
  return articleList
}