feat: add duff test units

Author: mirkobrombin

tests/diff_test.go

@@ -0,0 +1,96 @@
+package tests
+
+import (
+	"os"
+	"testing"
+
+	"github.com/vanilla-os/abroot/core"
+)
+
+// TestMergeDiff tests the MergeDiff function by creating 2 files with
+// different content and merging them into a destination file. The destination
+// file should reflect the changes.
+func TestMergeDiff(t *testing.T) {
+	firstFile := t.TempDir() + "/first"
+	err := os.WriteFile(firstFile, []byte("first file"), 0644)
+	if err != nil {
+		t.Error(err)
+	}
+
+	secondFile := t.TempDir() + "/second"
+	err = os.WriteFile(secondFile, []byte("second file"), 0644)
+	if err != nil {
+		t.Error(err)
+	}
+
+	destination := t.TempDir() + "/destination"
+
+	err = core.MergeDiff(firstFile, secondFile, destination)
+	if err != nil {
+		t.Error(err)
+	}
+
+	firstFileContents, err := os.ReadFile(firstFile)
+	if err != nil {
+		t.Error(err)
+	}
+
+	destinationContents, err := os.ReadFile(destination)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if string(firstFileContents) != string(destinationContents) {
+		t.Error("destination file does not have the same content as the second file")
+	}
+
+	t.Log("TestMergeDiff: destination file:", string(destinationContents))
+	t.Log("TestMergeDiff: done")
+}
+
+// TestDiffFiles tests the DiffFiles function in 2 cases:
+// 1. when the source and dest files have the same content
+// 2. when the source and dest files have different content
+func TestDiffFiles(t *testing.T) {
+	// same content
+	sourceFile := t.TempDir() + "/source"
+	err := os.WriteFile(sourceFile, []byte("same file"), 0644)
+	if err != nil {
+		t.Error(err)
+	}
+
+	destFile := t.TempDir() + "/dest"
+	err = os.WriteFile(destFile, []byte("same file"), 0644)
+	if err != nil {
+		t.Error(err)
+	}
+
+	diffLines, err := core.DiffFiles(sourceFile, destFile)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if diffLines != nil {
+		t.Error("diff lines should be nil")
+	}
+
+	t.Log("No diff found. Expected behavior.")
+
+	// different content
+	err = os.WriteFile(destFile, []byte("different file"), 0644)
+	if err != nil {
+		t.Error(err)
+	}
+
+	diffLines, err = core.DiffFiles(sourceFile, destFile)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if diffLines == nil {
+		t.Error("diff lines should not be nil")
+	}
+
+	t.Log("Diff: ", string(diffLines))
+	t.Log("Diff found. Expected behavior.")
+}