First commit

1 files changed, 118 insertions, 0 deletions

diff --git a/pkg/gitdiff/base85_test.go b/pkg/gitdiff/base85_test.go
new file mode 100644
index 0000000..672c471
--- /dev/null
+++ b/pkg/gitdiff/base85_test.go
@@ -0,0 +1,118 @@
+package gitdiff
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestBase85Decode(t *testing.T) {
+	tests := map[string]struct {
+		Input  string
+		Output []byte
+		Err    bool
+	}{
+		"twoBytes": {
+			Input:  "%KiWV",
+			Output: []byte{0xCA, 0xFE},
+		},
+		"fourBytes": {
+			Input:  "007GV",
+			Output: []byte{0x0, 0x0, 0xCA, 0xFE},
+		},
+		"sixBytes": {
+			Input:  "007GV%KiWV",
+			Output: []byte{0x0, 0x0, 0xCA, 0xFE, 0xCA, 0xFE},
+		},
+		"invalidCharacter": {
+			Input: "00'GV",
+			Err:   true,
+		},
+		"underpaddedSequence": {
+			Input: "007G",
+			Err:   true,
+		},
+		"dataUnderrun": {
+			Input:  "007GV",
+			Output: make([]byte, 8),
+			Err:    true,
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			dst := make([]byte, len(test.Output))
+			err := base85Decode(dst, []byte(test.Input))
+			if test.Err {
+				if err == nil {
+					t.Fatalf("expected error decoding base85 data, but got nil")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error decoding base85 data: %v", err)
+			}
+			for i, b := range test.Output {
+				if dst[i] != b {
+					t.Errorf("incorrect byte at index %d: expected 0x%X, actual 0x%X", i, b, dst[i])
+				}
+			}
+		})
+	}
+}
+
+func TestBase85Encode(t *testing.T) {
+	tests := map[string]struct {
+		Input  []byte
+		Output string
+	}{
+		"zeroBytes": {
+			Input:  []byte{},
+			Output: "",
+		},
+		"twoBytes": {
+			Input:  []byte{0xCA, 0xFE},
+			Output: "%KiWV",
+		},
+		"fourBytes": {
+			Input:  []byte{0x0, 0x0, 0xCA, 0xFE},
+			Output: "007GV",
+		},
+		"sixBytes": {
+			Input:  []byte{0x0, 0x0, 0xCA, 0xFE, 0xCA, 0xFE},
+			Output: "007GV%KiWV",
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			dst := make([]byte, len(test.Output))
+			base85Encode(dst, test.Input)
+			for i, b := range test.Output {
+				if dst[i] != byte(b) {
+					t.Errorf("incorrect character at index %d: expected '%c', actual '%c'", i, b, dst[i])
+				}
+			}
+		})
+	}
+}
+
+func FuzzBase85Roundtrip(f *testing.F) {
+	f.Add([]byte{0x2b, 0x0d})
+	f.Add([]byte{0xbc, 0xb4, 0x3f})
+	f.Add([]byte{0xfa, 0x62, 0x05, 0x83, 0x24, 0x39, 0xd5, 0x25})
+	f.Add([]byte{0x31, 0x59, 0x02, 0xa0, 0x61, 0x12, 0xd9, 0x43, 0xb8, 0x23, 0x1a, 0xb4, 0x02, 0xae, 0xfa, 0xcc, 0x22, 0xad, 0x41, 0xb9, 0xb8})
+
+	f.Fuzz(func(t *testing.T, in []byte) {
+		n := len(in)
+		dst := make([]byte, base85Len(n))
+		out := make([]byte, n)
+
+		base85Encode(dst, in)
+		if err := base85Decode(out, dst); err != nil {
+			t.Fatalf("unexpected error decoding base85 data: %v", err)
+		}
+		if !bytes.Equal(in, out) {
+			t.Errorf("decoded data differed from input data:\n   input: %x\n  output: %x\nencoding: %s\n", in, out, string(dst))
+		}
+	})
+}