Implement rpc05 specVersion (#416)

* Implement rpc05 specVersion

README.md

@@ -115,6 +115,7 @@ go run main.go
 | `starknet_addDeployAccountTransaction`     | :heavy_check_mark: |
 | `starknet_traceTransaction`                | :heavy_check_mark: |
 | `starknet_simulateTransaction`             | :heavy_check_mark: |
+| `starknet_specVersion`                     | :heavy_check_mark: |
 | `starknet_traceBlockTransactions`          | :heavy_check_mark: |
 
 ### Run Tests

account/account.go

@@ -389,6 +389,9 @@ func (account *Account) StorageAt(ctx context.Context, contractAddress *felt.Fel
 func (account *Account) StateUpdate(ctx context.Context, blockID rpc.BlockID) (*rpc.StateUpdateOutput, error) {
 	return account.provider.StateUpdate(ctx, blockID)
 }
+func (account *Account) SpecVersion(ctx context.Context) (string, error) {
+	return account.provider.SpecVersion(ctx)
+}
 func (account *Account) Syncing(ctx context.Context) (*rpc.SyncStatus, error) {
 	return account.provider.Syncing(ctx)
 }

rpc/provider.go

@@ -46,6 +46,7 @@ type RpcProvider interface {
 	SimulateTransactions(ctx context.Context, blockID BlockID, txns []Transaction, simulationFlags []SimulationFlag) ([]SimulatedTransaction, error)
 	StateUpdate(ctx context.Context, blockID BlockID) (*StateUpdateOutput, error)
 	StorageAt(ctx context.Context, contractAddress *felt.Felt, key string, blockID BlockID) (string, error)
+	SpecVersion(ctx context.Context) (string, error)
 	Syncing(ctx context.Context) (*SyncStatus, error)
 	TraceBlockTransactions(ctx context.Context, blockHash *felt.Felt) ([]Trace, error)
 	TransactionByBlockIdAndIndex(ctx context.Context, blockID BlockID, index uint64) (Transaction, error)

rpc/version.go

@@ -0,0 +1,12 @@
+package rpc
+
+import "context"
+
+// SpecVersion returns the version of the Starknet JSON-RPC specification being used
+// Parameters: None
+// Returns: String of the Starknet JSON-RPC specification
+func (provider *Provider) SpecVersion(ctx context.Context) (string, error) {
+	var result string
+	err := do(ctx, provider.c, "starknet_specVersion", &result)
+	return result, err
+}

rpc/version_test.go

@@ -0,0 +1,32 @@
+package rpc
+
+import (
+	"context"
+	"testing"
+
+	"github.com/test-go/testify/require"
+)
+
+// TestSpecVersion tests starknet_specVersion
+func TestSpecVersion(t *testing.T) {
+
+	testConfig := beforeEach(t)
+
+	type testSetType struct {
+		ExpectedResp string
+	}
+	testSet := map[string][]testSetType{
+		"devnet":  {},
+		"mainnet": {},
+		"mock":    {},
+		"testnet": {{
+			ExpectedResp: "0.5.0",
+		}},
+	}[testEnv]
+
+	for _, test := range testSet {
+		resp, err := testConfig.provider.SpecVersion(context.Background())
+		require.NoError(t, err)
+		require.Equal(t, test.ExpectedResp, resp)
+	}
+}