ax(mining): rename errors_test.go functions to TestErrors_Function_{Good,Bad,Ugly}

Test names lacked the AX-required suffix pattern (RFC-025 §10 test naming).
Renamed all 8 functions to TestErrors_* with _Good, _Bad, and _Ugly suffixes.
Also renamed loop variables from tt to c (predictable name, AX principle 1).

Co-Authored-By: Charon <charon@lethean.io>

pkg/mining/errors_test.go

@@ -6,7 +6,8 @@ import (
 	"testing"
 )
 
-func TestMiningError_Error(t *testing.T) {
+// TestErrors_Error_Good verifies the error string format with no cause
+func TestErrors_Error_Good(t *testing.T) {
 	err := NewMiningError(ErrCodeMinerNotFound, "miner not found")
 	expected := "MINER_NOT_FOUND: miner not found"
 	if err.Error() != expected {
@@ -14,22 +15,22 @@ func TestMiningError_Error(t *testing.T) {
 	}
 }
 
-func TestMiningError_ErrorWithCause(t *testing.T) {
+// TestErrors_Error_Bad verifies the error string includes the underlying cause
+func TestErrors_Error_Bad(t *testing.T) {
 	cause := errors.New("underlying error")
 	err := NewMiningError(ErrCodeStartFailed, "failed to start").WithCause(cause)
 
-	// Should include cause in error message
 	if err.Cause != cause {
 		t.Error("Cause was not set")
 	}
 
-	// Should be unwrappable
 	if errors.Unwrap(err) != cause {
 		t.Error("Unwrap did not return cause")
 	}
 }
 
-func TestMiningError_WithDetails(t *testing.T) {
+// TestErrors_WithDetails_Good verifies details are attached to the error
+func TestErrors_WithDetails_Good(t *testing.T) {
 	err := NewMiningError(ErrCodeInvalidConfig, "invalid config").
 		WithDetails("port must be between 1024 and 65535")
 
@@ -38,7 +39,8 @@ func TestMiningError_WithDetails(t *testing.T) {
 	}
 }
 
-func TestMiningError_WithSuggestion(t *testing.T) {
+// TestErrors_WithSuggestion_Good verifies suggestions are attached to the error
+func TestErrors_WithSuggestion_Good(t *testing.T) {
 	err := NewMiningError(ErrCodeConnectionFailed, "connection failed").
 		WithSuggestion("check your network")
 
@@ -47,8 +49,9 @@ func TestMiningError_WithSuggestion(t *testing.T) {
 	}
 }
 
-func TestMiningError_StatusCode(t *testing.T) {
-	tests := []struct {
+// TestErrors_StatusCode_Good verifies each error constructor returns the correct HTTP status
+func TestErrors_StatusCode_Good(t *testing.T) {
+	cases := []struct {
 		name     string
 		err      *MiningError
 		expected int
@@ -61,17 +64,18 @@ func TestMiningError_StatusCode(t *testing.T) {
 		{"timeout", ErrTimeout("operation"), http.StatusGatewayTimeout},
 	}
 
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if tt.err.StatusCode() != tt.expected {
-				t.Errorf("Expected status %d, got %d", tt.expected, tt.err.StatusCode())
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if c.err.StatusCode() != c.expected {
+				t.Errorf("Expected status %d, got %d", c.expected, c.err.StatusCode())
 			}
 		})
 	}
 }
 
-func TestMiningError_IsRetryable(t *testing.T) {
-	tests := []struct {
+// TestErrors_IsRetryable_Good verifies retryable vs non-retryable classifications
+func TestErrors_IsRetryable_Good(t *testing.T) {
+	cases := []struct {
 		name      string
 		err       *MiningError
 		retryable bool
@@ -86,17 +90,18 @@ func TestMiningError_IsRetryable(t *testing.T) {
 		{"database error", ErrDatabaseError("query"), true},
 	}
 
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if tt.err.IsRetryable() != tt.retryable {
-				t.Errorf("Expected retryable=%v, got %v", tt.retryable, tt.err.IsRetryable())
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if c.err.IsRetryable() != c.retryable {
+				t.Errorf("Expected retryable=%v, got %v", c.retryable, c.err.IsRetryable())
 			}
 		})
 	}
 }
 
-func TestPredefinedErrors(t *testing.T) {
-	tests := []struct {
+// TestErrors_PredefinedErrors_Good verifies each error constructor sets the correct code and message
+func TestErrors_PredefinedErrors_Good(t *testing.T) {
+	cases := []struct {
 		name string
 		err  *MiningError
 		code string
@@ -117,19 +122,20 @@ func TestPredefinedErrors(t *testing.T) {
 		{"ErrInternal", ErrInternal("unexpected error"), ErrCodeInternalError},
 	}
 
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			if tt.err.Code != tt.code {
-				t.Errorf("Expected code %s, got %s", tt.code, tt.err.Code)
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if c.err.Code != c.code {
+				t.Errorf("Expected code %s, got %s", c.code, c.err.Code)
 			}
-			if tt.err.Message == "" {
+			if c.err.Message == "" {
 				t.Error("Message should not be empty")
 			}
 		})
 	}
 }
 
-func TestMiningError_Chaining(t *testing.T) {
+// TestErrors_Chaining_Ugly verifies error chaining survives multiple WithCause/WithDetails/WithSuggestion calls
+func TestErrors_Chaining_Ugly(t *testing.T) {
 	cause := errors.New("network timeout")
 	err := ErrConnectionFailed("pool:3333").
 		WithCause(cause).