diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index 11b65fb..92be03c 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -7,8 +7,21 @@ on:
   schedule:
     - cron: "0 0 * * *"
 jobs:
+  test:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v4
+        with:
+          go-version: "stable"
+      - run: go test ./... -v
+
   build:
     runs-on: ubuntu-latest
+    needs: test
     permissions:
       contents: read
       packages: write
diff --git a/Dockerfile b/Dockerfile
index ff0a351..ef5afcd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,6 +7,6 @@ COPY go.mod go.sum ./
 RUN go mod download && go mod verify
 
 COPY . .
-RUN go build -v -o /usr/local/bin/app ./...
+RUN go test ./... && go build -v -o /usr/local/bin/app ./...
 
 CMD ["app"]
diff --git a/main.go b/main.go
index af57467..0d81255 100644
--- a/main.go
+++ b/main.go
@@ -24,6 +24,10 @@ func init() {
 }
 
 func GetPostsFromReddit(subreddit string) (string, error) {
+	if subreddit == "" {
+		return "", fmt.Errorf("subreddit cannot be empty")
+	}
+
 	client, err := reddit.NewReadonlyClient()
 	if err != nil {
 		log.Println("Failed to create Reddit client:", err)
@@ -37,7 +41,12 @@ func GetPostsFromReddit(subreddit string) (string, error) {
 		Time: "all",
 	})
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("failed to get posts from Reddit: %v", err)
+	}
+
+	// Check if the subreddit exists
+	if len(posts) == 0 {
+		return "", fmt.Errorf("subreddit '%v' does not exist", subreddit)
 	}
 
 	// [Title](<https://old.reddit.com{Permalink}>)\n{URL}
diff --git a/main_test.go b/main_test.go
new file mode 100644
index 0000000..52a47e0
--- /dev/null
+++ b/main_test.go
@@ -0,0 +1,35 @@
+package main
+
+import (
+	"testing"
+)
+
+// Returns a string with a length between 1 and 2000 characters
+func TestGetPostsFromReddit_ReturnsPostWithValidLength(t *testing.T) {
+	subreddit := "celebs"
+	post, err := GetPostsFromReddit(subreddit)
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if len(post) < 1 || len(post) > 2000 {
+		t.Errorf("Post length is not within the valid range")
+	}
+}
+
+// Returns an error when the subreddit does not exist
+func TestGetPostsFromReddit_ReturnsErrorWhenSubredditDoesNotExist(t *testing.T) {
+	subreddit := "nonexistent"
+	_, err := GetPostsFromReddit(subreddit)
+	if err == nil {
+		t.Errorf("Expected error, but got nil")
+	}
+}
+
+// Returns an error when the subreddit is empty
+func TestGetPostsFromReddit_ReturnsErrorWhenSubredditIsEmpty(t *testing.T) {
+	subreddit := ""
+	_, err := GetPostsFromReddit(subreddit)
+	if err.Error() != "subreddit cannot be empty" {
+		t.Errorf("Expected error 'subreddit cannot be empty', but got '%v'", err)
+	}
+}
diff --git a/settings_test.go b/settings_test.go
new file mode 100644
index 0000000..6c13f58
--- /dev/null
+++ b/settings_test.go
@@ -0,0 +1,72 @@
+package main
+
+import (
+	"os"
+	"reflect"
+	"testing"
+)
+
+// Returns a Config object with DiscordToken set when DISCORD_TOKEN environment variable is set
+func TestLoadFromEnvironment_DiscordTokenSet(t *testing.T) {
+	os.Setenv("DISCORD_TOKEN", "test_token")
+	defer os.Unsetenv("DISCORD_TOKEN")
+
+	config, err := loadFromEnvironment()
+	if err != nil {
+		t.Errorf("Expected no error, but got: %v", err)
+	}
+
+	expected := &Config{
+		DiscordToken: "test_token",
+	}
+	if !reflect.DeepEqual(config, expected) {
+		t.Errorf("Expected config to be %v, but got %v", expected, config)
+	}
+}
+
+// Returns an error when DISCORD_TOKEN environment variable is empty
+func TestLoadFromEnvironment_EmptyDiscordToken(t *testing.T) {
+	os.Setenv("DISCORD_TOKEN", "")
+	defer os.Unsetenv("DISCORD_TOKEN")
+
+	_, err := loadFromEnvironment()
+	if err == nil {
+		t.Error("Expected an error, but got nil")
+	}
+
+	expected := "DISCORD_TOKEN environment variable not set or empty. Also tried reading from settings.json file"
+	if err.Error() != expected {
+		t.Errorf("Expected error message to be '%s', but got '%s'", expected, err.Error())
+	}
+}
+
+// Returns an error when DISCORD_TOKEN environment variable is not set and settings.json file is not present
+func TestLoadFromEnvironment_NoDiscordTokenNoSettingsFile(t *testing.T) {
+	os.Unsetenv("DISCORD_TOKEN")
+
+	_, err := loadFromEnvironment()
+	if err == nil {
+		t.Error("Expected an error, but got nil")
+	}
+
+	expected := "DISCORD_TOKEN environment variable not set or empty. Also tried reading from settings.json file"
+	if err.Error() != expected {
+		t.Errorf("Expected error message to be '%s', but got '%s'", expected, err.Error())
+	}
+}
+
+// Returns an error when settings.json file is present but DiscordToken is not set
+func TestLoadFromEnvironment_SettingsFileNoDiscordToken(t *testing.T) {
+	os.Setenv("DISCORD_TOKEN", "")
+	defer os.Unsetenv("DISCORD_TOKEN")
+
+	_, err := loadFromEnvironment()
+	if err == nil {
+		t.Error("Expected an error, but got nil")
+	}
+
+	expected := "DISCORD_TOKEN environment variable not set or empty. Also tried reading from settings.json file"
+	if err.Error() != expected {
+		t.Errorf("Expected error message to be '%s', but got '%s'", expected, err.Error())
+	}
+}