From 8ab4d0b364ef1e9af5d102531da20d5ec902b6c4 Mon Sep 17 00:00:00 2001
From: Abdullah Obaied <abdullah.obaied@gmail.com>
Date: Sat, 10 Feb 2018 16:18:52 +0100
Subject: [PATCH] Add Support for Deleting a File's Comments (#259)

Add support for deleting file comments
---
 files.go      |  23 +++++++++++
 files_test.go | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 129 insertions(+)
 create mode 100644 files_test.go

diff --git a/files.go b/files.go
index b531634d6..555d3a5b0 100644
--- a/files.go
+++ b/files.go
@@ -257,6 +257,29 @@ func (api *Client) UploadFileContext(ctx context.Context, params FileUploadParam
 	return &response.File, nil
 }
 
+// DeleteFileComment deletes a file's comment
+func (api *Client) DeleteFileComment(commentID, fileID string) error {
+	return api.DeleteFileCommentContext(context.Background(), fileID, commentID)
+}
+
+// DeleteFileCommentContext deletes a file's comment with a custom context
+func (api *Client) DeleteFileCommentContext(ctx context.Context, fileID, commentID string) (err error) {
+	if fileID == "" || commentID == "" {
+		return errors.New("received empty parameters")
+	}
+
+	values := url.Values{
+		"token": {api.token},
+		"file":  {fileID},
+		"id":    {commentID},
+	}
+	if _, err = fileRequest(ctx, api.httpclient, "files.comments.delete", values, api.debug); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // DeleteFile deletes a file
 func (api *Client) DeleteFile(fileID string) error {
 	return api.DeleteFileContext(context.Background(), fileID)
diff --git a/files_test.go b/files_test.go
new file mode 100644
index 000000000..ecb5c3360
--- /dev/null
+++ b/files_test.go
@@ -0,0 +1,106 @@
+package slack
+
+import (
+	"log"
+	"net/http"
+	"net/url"
+	"reflect"
+	"testing"
+)
+
+type fileCommentHandler struct {
+	gotParams map[string]string
+}
+
+func newFileCommentHandler() *fileCommentHandler {
+	return &fileCommentHandler{
+		gotParams: make(map[string]string),
+	}
+}
+
+func (h *fileCommentHandler) accumulateFormValue(k string, r *http.Request) {
+	if v := r.FormValue(k); v != "" {
+		h.gotParams[k] = v
+	}
+}
+
+func (h *fileCommentHandler) handler(w http.ResponseWriter, r *http.Request) {
+	h.accumulateFormValue("token", r)
+	h.accumulateFormValue("file", r)
+	h.accumulateFormValue("id", r)
+
+	w.Header().Set("Content-Type", "application/json")
+	if h.gotParams["id"] == "trigger-error" {
+		w.Write([]byte(`{ "ok": false, "error": "errored" }`))
+	} else {
+		w.Write([]byte(`{ "ok": true }`))
+	}
+}
+
+func TestSlack_DeleteFileComment(t *testing.T) {
+	once.Do(startServer)
+	SLACK_API = "http://" + serverAddr + "/"
+	api := New("testing-token")
+	tests := []struct {
+		title       string
+		body        url.Values
+		wantParams  map[string]string
+		expectError bool
+	}{
+		{
+			title: "Testing with proper body",
+			body: url.Values{
+				"file": {"file12345"},
+				"id":   {"id12345"},
+			},
+			wantParams: map[string]string{
+				"token": "testing-token",
+				"file":  "file12345",
+				"id":    "id12345",
+			},
+			expectError: false,
+		},
+		{
+			title: "Testing with false body",
+			body: url.Values{
+				"file": {""},
+				"id":   {""},
+			},
+			wantParams:  map[string]string{},
+			expectError: true,
+		},
+		{
+			title: "Testing with error",
+			body: url.Values{
+				"file": {"file12345"},
+				"id":   {"trigger-error"},
+			},
+			wantParams: map[string]string{
+				"token": "testing-token",
+				"file":  "file12345",
+				"id":    "trigger-error",
+			},
+			expectError: true,
+		},
+	}
+
+	var fch *fileCommentHandler
+	http.HandleFunc("/files.comments.delete", func(w http.ResponseWriter, r *http.Request) {
+		fch.handler(w, r)
+	})
+
+	for _, test := range tests {
+		fch = newFileCommentHandler()
+		err := api.DeleteFileComment(test.body["id"][0], test.body["file"][0])
+
+		if test.expectError == false && err != nil {
+			log.Fatalf("Unexpected error: %s in test", err, test.title)
+		} else if test.expectError == true && err == nil {
+			log.Fatalf("Expected error but got none")
+		}
+
+		if !reflect.DeepEqual(fch.gotParams, test.wantParams) {
+			log.Fatalf("%s: Got params [%#v]\nBut received [%#v]\n", test.title, fch.gotParams, test.wantParams)
+		}
+	}
+}