Check errors by identity, not by message text, in tests (closes #49)

Tests that asserted a failure by a fragment of its message now use
errors.Is: a refactor returning the wrong error, or wrapping with %v
instead of %w, now fails them. New tests return each exported error of
internal/vault and pkg/bip85 that no test returned, and check wrapped
causes (os.ErrNotExist, ErrMnemonicMismatch through GetSecret,
ErrInvalidPathComponent through DeriveBIP85Entropy). The 999-versions
test moves into package secret to name its unexported error. Checks of
errors no test can name keep their text; they are listed on the issue.

Model: opus-5-5

internal/cli/move_test.go

@@ -30,6 +30,8 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 		workX      = "work:x"
 	)
 
+	// internal/cli declares these errors itself and does not export them, so
+	// only their text can be compared.
 	tests := []struct {
 		command      string
 		source, dest string
@@ -52,21 +54,6 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 			"mv --force nosuch:x nosuch:y", "nosuch:x", "nosuch:y", true,
 			"vault 'nosuch' does not exist",
 		},
-		// Each of these spells "work" a second way. The spelling is not a
-		// valid vault name, so the move is not taken for a move between two
-		// vaults, which would delete the destination, here the source.
-		{
-			"mv --force work:x work/:x", workX, "work/:x", true,
-			vault.ValidateVaultName("work/").Error(),
-		},
-		{
-			"mv --force work/:x work:", "work/:x", "work:", true,
-			vault.ValidateVaultName("work/").Error(),
-		},
-		{
-			"mv --force work:x ./work:x", workX, "./work:x", true,
-			vault.ValidateVaultName("./work").Error(),
-		},
 	}
 
 	for _, tt := range tests {
@@ -82,6 +69,26 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 			require.EqualError(t, err, tt.wantErr)
 		})
 	}
+
+	// Each of these spells "work" a second way. The spelling is not a valid
+	// vault name, so the move is not taken for a move between two vaults,
+	// which would delete the destination, here the source.
+	invalidNames := []struct{ source, dest string }{
+		{workX, "work/:x"},
+		{"work/:x", "work:"},
+		{workX, "./work:x"},
+	}
+
+	for _, tt := range invalidNames {
+		t.Run("mv --force "+tt.source+" "+tt.dest, func(t *testing.T) {
+			t.Parallel()
+
+			requireRejectedAndUnchanged(t, before, vault.ErrInvalidVaultName,
+				func(c *cli.Instance) error {
+					return c.MoveSecret(&cobra.Command{}, tt.source, tt.dest, true)
+				})
+		})
+	}
 }
 
 // TestMoveWithinOtherVaultKeepsCurrentVault checks that `secret mv work:x