feat: add methods to test for the existence of a chain (#114)

Adds two methods `Exists` and `ExistsN` to the Blockchain struct to
check if a chain exists in the database.

`Exists` checks the existence of a single selector to return true.
`ExistsN` checks the existence of multiple selectors, all of which must
exist for the method to return true.

Author: jkongie

.changeset/angry-trains-end.md

@@ -0,0 +1,5 @@
+---
+"chainlink-deployments-framework": patch
+---
+
+Add `Exists` and `ExistsN` methods to `Blockchains` to test for the existence of a chain for the provided selector/s

chain/blockchain.go

@@ -16,6 +16,17 @@ var _ BlockChain = aptos.Chain{}
 var _ BlockChain = sui.Chain{}
 var _ BlockChain = ton.Chain{}
 
+// BlockChain is an interface that represents a chain.
+// A chain can be an EVM chain, Solana chain Aptos chain or others.
+type BlockChain interface {
+	// String returns chain name and selector "<name> (<selector>)"
+	String() string
+	// Name returns the name of the chain
+	Name() string
+	ChainSelector() uint64
+	Family() string
+}
+
 // BlockChains represents a collection of chains.
 // It provides querying capabilities for different types of chains.
 type BlockChains struct {
@@ -41,15 +52,22 @@ func NewBlockChains(chains map[uint64]BlockChain) BlockChains {
 	}
 }
 
-// BlockChain is an interface that represents a chain.
-// A chain can be an EVM chain, Solana chain Aptos chain or others.
-type BlockChain interface {
-	// String returns chain name and selector "<name> (<selector>)"
-	String() string
-	// Name returns the name of the chain
-	Name() string
-	ChainSelector() uint64
-	Family() string
+// Exists checks if a chain with the given selector exists.
+func (b BlockChains) Exists(selector uint64) bool {
+	_, ok := b.chains[selector]
+
+	return ok
+}
+
+// ExistsN checks if all chains with the given selectors exist.
+func (b BlockChains) ExistsN(selectors ...uint64) bool {
+	for _, selector := range selectors {
+		if !b.Exists(selector) {
+			return false
+		}
+	}
+
+	return true
 }
 
 // EVMChains returns a map of all EVM chains with their selectors.

chain/blockchain_test.go

@@ -47,6 +47,70 @@ func TestNewBlockChains(t *testing.T) {
 	})
 }
 
+func Test_BlockChains_Exists(t *testing.T) {
+	t.Parallel()
+
+	chains := buildBlockChains()
+
+	tests := []struct {
+		name     string
+		selector uint64
+		expected bool
+	}{
+		{
+			name:     "exists",
+			selector: evmChain1.Selector,
+			expected: true,
+		},
+		{
+			name:     "does not exist",
+			selector: 99999999,
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			exists := chains.Exists(tt.selector)
+			assert.Equal(t, tt.expected, exists)
+		})
+	}
+}
+
+func Test_BlockChains_ExistsN(t *testing.T) {
+	t.Parallel()
+
+	chains := buildBlockChains()
+
+	tests := []struct {
+		name      string
+		selectors []uint64
+		expected  bool
+	}{
+		{
+			name:      "all exist",
+			selectors: []uint64{evmChain1.Selector, solanaChain1.Selector},
+			expected:  true,
+		},
+		{
+			name:      "some do not exist",
+			selectors: []uint64{evmChain1.Selector, 99999999},
+			expected:  false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			exists := chains.ExistsN(tt.selectors...)
+			assert.Equal(t, tt.expected, exists)
+		})
+	}
+}
+
 func TestBlockChainsEVMChains(t *testing.T) {
 	t.Parallel()