Error when running examples/compare-tokens.rs and examples/custom_deserialization.rs

[nsipplswezey]

When running the compare-tokens and custom_deserialization examples locally using the following:

SCYLLA_URI="127.0.0.1:9042" cargo run --example compare-tokens
SCYLLA_URI="127.0.0.1:9042" cargo run --example custom_deserialization

The scylla-rust-driver reports table-related errors such as:

scylla-rust-driver % cargo run --example custom_deserialization
    Finished dev [unoptimized + debuginfo] target(s) in 0.38s
     Running `target/debug/examples/custom_deserialization`
Connecting to 127.0.0.1:9042 ...
Error: Database returned an error: The query is syntactically correct but invalid, Error message: Unknown identifier pk

scylla-rust-driver % cargo run --example compare-tokens        
    Finished dev [unoptimized + debuginfo] target(s) in 0.29s
     Running `target/debug/examples/compare-tokens`
Connecting to 127.0.0.1:9042 ...
Error: Database returned an error: The query is syntactically correct but invalid, Error message: Exception while binding column pk: marshaling error: Validation failed for type org.apache.cassandra.db.marshal.Int32Type: got 8 bytes

After taking a look it seems that these tests use the same simple ks for keyspace and ks.t for table naming convention for keyspace and table creation.

"CREATE TABLE IF NOT EXISTS ks.t (pk bigint primary key)",
"INSERT INTO ks.t (pk) VALUES (?)"
"INSERT INTO ks.t (pk) VALUES (?)"
"SELECT token(pk) FROM ks.t where pk = {}"
"CREATE TABLE IF NOT EXISTS ks.t (pk int PRIMARY KEY, v text)"
"INSERT INTO ks.t (pk, v) VALUES (1, 'asdf')"

When running against a local Scylla cluster, ks.t persists between example runs causing examples to run inconsistently. These two examples would error in different ways depending on when they were run... and dropping ks.t as needed resolved the issue. This issue also persisted when running examples in my own CI environment on my own scylla-rust-driver fork.

[nsipplswezey]

Proposed fix/improvement: #846