add some tests

client/client.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 )
 
 var (
@@ -17,13 +18,6 @@ type Client struct {
 	apipath    string
 }
 
-// NewClient returns a new Client struct using http.DefaultClient and default api path.
-func NewClient() (*Client, error) {
-	return &Client{
-		apipath: defaultAPI,
-	}, nil
-}
-
 // SetHTTPClient updates the httpClient on the client with a manually-configured one.
 // If unset, the client will fall back to using http.DefaultClient.
 func (c *Client) SetHTTPClient(h http.Client) {
@@ -38,24 +32,38 @@ func (c *Client) SetAPIPath(p string) {
 
 // GetByISBN fetches details for a book based on its ISBN10 or ISBN13.
 func (c *Client) GetByISBN(k string) (*BookDetails, error) {
+	if k == "" {
+		return nil, fmt.Errorf("ISBN cannot be empty")
+	} else if len(k) != 10 && len(k) != 13 {
+		return nil, fmt.Errorf("ISBN must be either 10 or 13 digits")
+	}
 	key := "ISBN:" + k
 	return c.fetch(key)
 }
 
 // GetByOCLC fetches details for a book based on its WorldCat OCLC number.
 func (c *Client) GetByOCLC(k string) (*BookDetails, error) {
+	if k == "" {
+		return nil, fmt.Errorf("OCLC cannot be empty")
+	}
 	key := "OCLC:" + k
 	return c.fetch(key)
 }
 
 // GetByLCCN fetches details for a book based on its Library of Congress Control Number.
 func (c *Client) GetByLCCN(k string) (*BookDetails, error) {
+	if k == "" {
+		return nil, fmt.Errorf("LCCN cannot be empty")
+	}
 	key := "LCCN:" + k
 	return c.fetch(key)
 }
 
 // GetByOLID fetches details for a book based on its OpenLibrary ID number.
 func (c *Client) GetByOLID(k string) (*BookDetails, error) {
+	if k == "" {
+		return nil, fmt.Errorf("OLID cannot be empty")
+	}
 	key := "OLID:" + k
 	return c.fetch(key)
 }
@@ -68,12 +76,21 @@ func (c *Client) GetByRawKey(k string) (*BookDetails, error) {
 }
 
 func (c *Client) fetch(key string) (*BookDetails, error) {
-	path := c.apipath
-	if path == "" {
-		path = defaultAPI
+	h := c.apipath
+	if h == "" {
+		h = defaultAPI
 	}
+	u, err := url.Parse(h)
+	if err != nil {
+		return nil, err
+	}
+	u.RawQuery = url.Values{
+		"bibkeys": []string{key},
+		"jscmd":   []string{"data"},
+		"format":  []string{"json"},
+	}.Encode()
 
-	resp, err := c.httpClient.Get(path + "?bibkeys=%s&jscmd=data&format=json")
+	resp, err := c.httpClient.Get(u.String())
 	if err != nil {
 		return nil, err
 	}