add file source digest support (#1914)

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

internal/file/digest_test.go

@@ -0,0 +1,132 @@
+package file
+
+import (
+	"crypto"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/anchore/syft/syft/file"
+)
+
+func TestCleanDigestAlgorithmName(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "go case",
+			input: "SHA-256",
+			want:  "sha256",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, CleanDigestAlgorithmName(tt.input))
+		})
+	}
+}
+
+func TestNewDigestsFromFile(t *testing.T) {
+	require.NotEmpty(t, supportedHashAlgorithms())
+
+	tests := []struct {
+		name    string
+		fixture string
+		hashes  []crypto.Hash
+		want    []file.Digest
+		wantErr require.ErrorAssertionFunc
+	}{
+		{
+			name:    "check supported hash algorithms",
+			fixture: "test-fixtures/digest.txt",
+			hashes:  supportedHashAlgorithms(),
+			want: []file.Digest{
+				{
+					Algorithm: "md5",
+					Value:     "e8818a24402ae7f8b874cdd9350c1b51",
+				},
+				{
+					Algorithm: "sha1",
+					Value:     "eea4671d168c81fd52e615ed9fb3531a526f4748",
+				},
+				{
+					Algorithm: "sha224",
+					Value:     "fd993e84c7afb449d34bcae7c5ee118f5c73b50170da05171523b22c",
+				},
+				{
+					Algorithm: "sha256",
+					Value:     "cbf1a703b7e4a67529d6e17114880dfa9f879f3749872e1a9d4a20ac509165ad",
+				},
+				{
+					Algorithm: "sha384",
+					Value:     "1eaded3f17fb8d7b731c9175a0f355d3a35575c3cb6cdda46a5272b632968d7257a5e6437d0efae599a81a1b2dcc81ba",
+				},
+				{
+					Algorithm: "sha512",
+					Value:     "b49d5995456edba144dce750eaa8eae12af8fd08c076d401fcf78aac4172080feb70baaa5ed8c1b05046ec278446330fbf77e8ca9e60c03945ded761a641a7e1",
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.wantErr == nil {
+				tt.wantErr = require.NoError
+			}
+
+			fh, err := os.Open(tt.fixture)
+			require.NoError(t, err)
+
+			got, err := NewDigestsFromFile(fh, tt.hashes)
+			tt.wantErr(t, err)
+			if err != nil {
+				return
+			}
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
+func TestHashers(t *testing.T) {
+	tests := []struct {
+		name    string
+		names   []string
+		want    []crypto.Hash
+		wantErr require.ErrorAssertionFunc
+	}{
+		{
+			name:  "check supported hash algorithms",
+			names: []string{"MD-5", "shA1", "sHa224", "sha---256", "sha384", "sha512"},
+			want: []crypto.Hash{
+				crypto.MD5,
+				crypto.SHA1,
+				crypto.SHA224,
+				crypto.SHA256,
+				crypto.SHA384,
+				crypto.SHA512,
+			},
+		},
+		{
+			name:    "error on unsupported hash algorithm",
+			names:   []string{"made-up"},
+			wantErr: require.Error,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.wantErr == nil {
+				tt.wantErr = require.NoError
+			}
+			got, err := Hashers(tt.names...)
+			tt.wantErr(t, err)
+			if err != nil {
+				return
+			}
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}