Adding test coverage to faketerm.

private/faketerm/diff_test.go

@@ -0,0 +1,69 @@
+package faketerm
+
+import (
+	"image"
+	"testing"
+
+	"github.com/mum4k/termdash/cell"
+)
+
+func TestDiff(t *testing.T) {
+	tests := []struct {
+		desc     string
+		term1    *Terminal
+		term2    *Terminal
+		wantDiff bool
+	}{
+		{
+			desc: "no diff on equal terminals",
+			term1: func() *Terminal {
+				t := MustNew(image.Point{2, 2})
+				t.SetCell(image.Point{0, 0}, 'a')
+				return t
+			}(),
+			term2: func() *Terminal {
+				t := MustNew(image.Point{2, 2})
+				t.SetCell(image.Point{0, 0}, 'a')
+				return t
+			}(),
+			wantDiff: false,
+		},
+		{
+			desc: "reports diff on when cell runes differ",
+			term1: func() *Terminal {
+				t := MustNew(image.Point{2, 2})
+				t.SetCell(image.Point{0, 0}, 'a')
+				return t
+			}(),
+			term2: func() *Terminal {
+				t := MustNew(image.Point{2, 2})
+				t.SetCell(image.Point{1, 1}, 'a')
+				return t
+			}(),
+			wantDiff: true,
+		},
+		{
+			desc: "reports diff on when cell options differ",
+			term1: func() *Terminal {
+				t := MustNew(image.Point{2, 2})
+				t.SetCell(image.Point{0, 0}, 'a', cell.Bold())
+				return t
+			}(),
+			term2: func() *Terminal {
+				t := MustNew(image.Point{2, 2})
+				t.SetCell(image.Point{0, 0}, 'a')
+				return t
+			}(),
+			wantDiff: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.desc, func(t *testing.T) {
+			gotDiff := Diff(tc.term1, tc.term2)
+			if (gotDiff != "") != tc.wantDiff {
+				t.Errorf("Diff -> unexpected diff while wantDiff:%v, the diff:\n%s", tc.wantDiff, gotDiff)
+			}
+		})
+	}
+}